Another of Roberto Martinez's second-half introductions - Nacer Chadli - won it for the Red Devils with the last kick of the game as Belgium countered from a Japan corner.
Relive the drama of another superb World Cup game with Sports Mole's minute-by-minute updates below.
6.00pmGermany, Argentina, Spain...the big boys are dropping like flies at this World Cup and the road to glory in Russia is opening up nicely for a surprise winner. Can Belgian's golden generation turn their talent into an historic triumph? Japan are their next test in this last-16 encounter in Rostov...
6.04pmThe team news is in, let's start with Belgium who made nine changes for their final group game with England...
BELGIUM: Courtois; Alderweireld, Kompany, Vertonghen; Meunier, Witsel, De Bruyne, Carrasco; Mertens, Hazard, Lukaku Subs: To follow...
6.06pmJAPAN: Kawashima; H. Sakai, Yoshida, Shoji, Nagatomo; Hasebe, Shibasaki; Haraguchi, Kagawa, Inui; Osako Subs: To follow...
6.08pmRoberto Martinez has trumped himself by changing his entire starting XI. Dedryk Boyata was the only outfield player to retain his place for the dead rubber with England but makes way for Vincent Kompany now that Belgium's inspirational captain is fit again. He had 20 minutes against England last Thursday.
6.10pmOtherwise, the Red Devils revert to the lineup which began their opening Group G game against Panama. Romelu Lukaku, who is one short of England's Harry Kane in the race for the Golden Boot with four to his name so far, starts up front with Eden Hazard and Dries Mertens just in behind.
6.12pmTottenham Hotspur pair Toby Alderweireld and Jan Vertonghen flank Kompany in the back three, and their telepathic understanding from club level will be a big comfort blanket for the Manchester City defender as he nurses his way back from injury. That trio shield Chelsea's Thibaut Courtois in goal.
6.14pmKevin De Bruyne completes the seven-strong Premier League representation in this Belgium side, although the world-class playmaker has yet to really get going at this tournament. There have been reports of friction between him and Martinez, who is accused of playing the assist-king too deep.
6.16pmDespite taking up semi-retirement in China, Axel Witsel continues to get the nod as De Bruyne's midfield partner. Marouane Fellaini, who has just signed a new contract at Manchester United, and Tottenham's Mousa Dembele drop to the bench. To keep out Dembele, the 29-year-old must be some player.
6.18pmAlso dropping out is Adnan Januzaj, the match-winner against England with a strike which reminded everyone of his promising breakthrough at Old Trafford. While the now-Real Sociedad winger was one of few who made an impression in that game, it is difficult to see where he would fit in this side.
6.20pmWith Thomas Vermaelen fit again, Martinez had the option to shift Vertonghen over to wing-back but has persisted with Yannick Carrasco, another who plays his football in the Far East these days. The former Atletico Madrid winger is very new to this position and could be a defensive liability.
6.22pmOnto Japan, who make six changes themselves after rotating for the 1-0 defeat to Poland. Attacking midfield trio Shinji Kagawa, Takashi Inui and Genki Haraguchi all return, as does striker striker Yuya Osako with Leicester City star Shinji Okazaki unfit to start because of an ankle complaint.
6.24pmOkazaki is the most-capped player in the Japan squad having made 116 international appearances, scoring a half-century of goals. The Blue Samurai still have plenty of experience in the team though, including captain Makoto Hasebe who is back in for Takashi Usami after taking a rest.
6.26pmJapan's other alteration is a straight swap at centre-half as Gen Shoji replaces Tomoaki Makino. Shoj, who plays his club football for Kashima Antlers, is the only Japanese-based player in the XI.
6.28pmShoj's defensive partner is the very familiar Maya Yoshida, who has spent the last six years at Southampton. Yoshida had mixed luck up against Lukaku last season, conceding one to the Manchester United powerhouse at St Mary's but keeping the striker quiet at Old Trafford.
6.30pmThe Blue Samurai have never won a World Cup knockout game - they have made it to this stage on two previous occasions but were eliminated in the last 16 in both 2002 and 2010. Akira Nishino's side are undoubtedly the underdogs tonight but than is a tag they quite like in the footballing world.
6.32pmJapan have already made history at this tournament, becoming the first team to qualify for the knockout phase on the fair-play rule. They finished Group H with an identical record to Senegal but went through by virtue of having accumulated two fewer yellow cards than the African nation.
6.34pmIf you're hoping for another France vs. Argentina, you may be disappointed as Japan's two previous knockout games at the World Cup have produced only one goal, for Turkey in 2002 (0-1). The other game ended 0-0 after extra time against Paraguay in 2010 with Japan losing 5-3 on penalties.
6.36pmJapan have won just two of their nine World Cup games against European opposition. They have played Belgium previously at the World Cup - drawing 2-2 in their opening match as hosts in 2002.
6.38pmBelgium still managed to reach the knockout stage back in 2002, and they have actually made it through the group on six of their seven World Cup appearances, the only exception coming in 1998. However, they have only converted six last-16 appearances to two in the quarter-finals.
6.40pmSince losing his first game in charge to Spain, the Red Devils have gone 22 games unbeaten under manager Roberto Martinez and have taken that form into this tournament. They were one of only three teams to win all three of their group matches, even if the England match was a bit of a farce.
6.42pmMartinez's side were the highest scorers in the group stage with nine goals, of which four were bagged by Lukaku. His rest against England has allowed Belgium's all-time top scorer, who has 22 goals in his last 20 international appearances, to shake off an ankle knock and return to full fitness.
6.44pmThis Belgium side are more than an ensemble of exciting attackers though, they appear to be perfectly balanced from back to front. Courtois and company have kept two clean sheets in their last three World Cup matches, which is as many as Belgium recorded in their previous 11 combined.
6.46pmHowever, Belgium have never kept a clean sheet in their 11 knockout games at the World Cup, which should make it not too surprising that they have lost eight of them with only two wins.
6.48pmHEAD TO HEAD: Belgium have won only one of their five encounters with Japan, although that came in their last meeting in November 2017 when they won 1-0 thanks to a Lukaku goal. That 2002 meeting is one of two draws, with Japan coming out on top in the other pair of encounters.
6.50pmAround 10 minutes until kickoff here at the Rostov Arena, which is hosting its final match of the tournament. The four previous games have averaged 2.25 goals and an attendance of over 43,000.
6.52pmThe two teams are out for the national anthems. Going along the Belgium line it really is difficult to pick out a weakness, a reason why they can't win the World Cup for the first time ever.
6.54pmThen again, have Belgium already won the World Cup? Will anything eclipse this moment from Michy Batshuayi?
6.56pmBoth teams should be refreshed rather than leggy considering the wholesale changes made for their final group games. Japan's loss to Poland was even more friendly than Belgium's meeting with England, with the action practically coming to a standstill late on as Japan sat on the result that would take them through.
6.58pmPREDICTION: Japan knock the ball around nicely but I don't think they will be able to compete with the physicality or goal threat of Belgium, who I expect will win 2-0 to book a date with Brazil.
1 minKICKOFF: We are underway in Rostov where our officials are from Senegal, led by referee Malang Diedhiou. Bit late for him to dish out the yellow cards to Japan and bring his country back!
2 minSHOT! Kagawa works some space on the edge of the box for an early sighter, dragging a left-footed shot just a few yards wide after a poor clearing header from Carrasco.
4 minThe Blue Samurai have made a good start here, with Hiroki Sakai making a good run forward from right-back and making a mockery again of Carrasco's defensive ability as he is sycthed down.
6 minSakai has been one of Japan's standout performers during this tournament along with Takashi Inui, the Real Betis winger who is operating on the left tonight, giving the team a threat from both flanks.
8 minBelgium get the ball into Lukaku's feet for the first time and he finds a pass around the corner for Carrasco. The attacking third is where he is far more comfortable but nothing comes of this venture forward as Yoshida stalls him in a central position.
10 minThere are 58 places between these two sides in the FIFA World Rankings, but you wouldn't know it based on this opening 10 minutes. Another decent Japanese attack gets cleared to Shoji but his ambitious shot is high and wide to the right.
12 minDe Bruyne has struggled to get on the ball as of yet. Both teams are pressing quite hard and it isn't leaving the midfielders with much time on the ball. Japan are dealing with this pace is better at the moment, passing quicker through midfield.
14 minCarrasco turns away from Sakai on the edge of the box and is caught on the ankle. It is a foul and if the Belgian goes down he may have been given a penalty, but his honesty in staying on his feet counts against him on this occasion.
16 minWitsel lines up a speculative left-footed shot which is deflected over the crossbar for the first corner of the game. Belgium take it short, which is a surprise considering their height advantage over Japan, and De Bruyne's eventual cross is too heavy for Kompany to make anything of it.
18 minMeunier cushions De Bruyne's switch of play into the penalty area with a lovely header, and Lukaku is able to bring the ball down and turn but Yoshida stays close to him to deflect the shot behind.
20 minShibasaki takes a risk with the ball on the edge of his own box and nearly loses it to Hazard. The Chelsea star would have been in on goal but Yoshida comes across to help his mate recover.
22 minThe Red Devils try another training-ground corner routine, with De Bruyne pulling the ball back low behind the penalty spot for Mertens, who fails to make contact with a difficult left-vooted volley.
24 minWitsel plays a decent ball in between the lines for Meunier, but his attempt to knock it on to Lukaku first time was terribly underhit and easily intercepted. Belgium's wing-backs are playing very high.
26 minCHANCE! Lukaku just can't sort his feet out in the six yard box, otherwise Belgium would be ahead. The big man gets in front of his Premier League counterpart from a delightful Mertens cross but cannot bring the ball under control before it is cleared.
27 minSAVE! Belgium are moving through the gears now. A wonderful break involving Hazard and Mertens ends with De Bruyne being teed up for a 20-yard shot he completely miscues. Hazard catches his effort much sweeter, but Kawashima pushes away.
28 minJapan somehow survive a double scare, with Yoshida hacking a wild clearance only a few yards wide of his own post before goalkeeper Kawashima is stranded from a De Bruyne cross but Kompany can't quite divert it back towards a teammate at the far post.
30 minThis is a real test of this Japanese team now. Belgium have their tails up, will the Blue Samurai cower into a defensive shape or will they try to get back on the ball and create some chances of their own.
32 minCHANCE! We have our answer! Clever feet from Kagawa in the box helps him release Nagamoto on the overlap, and his cross is onto the head of Osako who can only not straight at Courtois.
34 minJapan come again with Hasebe knocking in an early cross but over the head of Osako. I admire Japan's response to the Belgium pressure but not sure that is their best route to a goal.
35 minA heavy touch lets Mertens down after Carraso had pulled a cross back perfectly for the Napoli forward.
37 minYoshida makes a crucial block from Hazard with Belgium's danger-man dribbling into the left side of the box. Witsel collects the second ball but his radar is all off again with a shot from distance.
39 minBelgium have had four corners already, and have knocked three of them beyond the back post. It seems as though the ploy is for Kompany or Vertonghen to knock the ball back across for their colleagues to win the second ball. With their aerial advantage, I'm not sure it needs to be that complicated!
41 minYELLOW! The first card of the game is shown to Getafe midfielder Shibasaki, who can't keep up with the dazzling Hazard. The Chelsea winger is checked on by the medics but will run this one off no problem. He is used to being in the wars weekly back in the Premier League.
43 minCarrasco has featured prominently in this first half, and mostly with promising attacking play. He hits a cross deep for the run of fellow wing-back Meunier, but Nagatomo wins an excellent clearing header.
45 minCLOSE! Courtois almost takes the social media attention off his pal Batshuayi here with an extraordinary error! Nagatomo cuts in from the left and gets off a weak shot which Osako tries to divert goalwards, and the distraction sees Courtois let the ball slip through his legs. A desperate dive is needed to avoid humiliation!
45+1 minLukaku appears to be offside but there is no flag and the layoff to Mertens sets up a shot which is held by Kawashima.
7.50pmIt may be too much to say that another shock is on the cards here, but Japan are well in this game. They withstood a Belgian barrage around the half-hour mark and finished the half with some decent moments of their own. Do they have the quality to get into the quarter-finals though?
7.54pmOne stat that otherwise-excellent link won't tell you is that Belgium have had 26 touches in the Japan box so far. That is more than any country has managed in a first half at this tournament.
7.56pmFair warning for Japan; it was goalless at the interval of today's other last-16 encounter and then Brazil's quality showed in the second period. If that is to happen today, Belgium need more from De Bruyne who has been on the periphary. Hazard and Lukaku have been good, it just hasn't happened for them yet.
7.58pmRemember, this could have been England playing Japan tonight had Gareth Southgate gone with a stronger team against Belgium last Thursday. It was suggested that the Blue Samurai would be weaker opponents than Colombia but they have shown so far that they are no pushovers.
8.00pmBENCH WATCH: Martinez has a plethora of options to turn to from the bench. Januzaj should be full of confidence after his goal against England, but the key to this match could be freeing up De Bruyne, and bringing Dembele on and switching to 4-2-3-1 would achieve that.
46 minKICKOFF: The second half is underway at the Rostov Arena, with both sides unchanged for now...
48 minOkay, now it is fair to say that a shock is on the cards! Japan take the lead on the break as captain Hasebe releases Haraguichi - one of four runners bursting forward - inside Vertonghen, who should cut the ball out, and the midfielder keeps his cool to pick out the bottom corner from 15 yards.
50 minWOODWORK! Belgium come within inches of an immediate response, with Mertens released down the right channel and pulling a cross back for Hazard who bends a shot against the post!
51 minMeunier's cross is just in front of Lukaku who was primed to head home a Belgian equaliser from 10 yards...
52 minJapan are dreaming of a World Cup quarter-final now! Kagawa's beautiful footwork on the edge of the box - under minimal Belgian pressure it must be said - creates a shooting chance for Inui and boy does he take it, arrowing a 25-yard shot across Courtois and into the bottom corner.
54 minBelgium's golden generation are on the ropes here. Another major tournament could slip them by. Are they too stunned to reply or can De Bruyne, Hazard and Lukaku muster a response?
56 minIt is time for Martinez to earn his money. He needs to sacrifice one of his defenders - or at least Carrasco to bring on another goal threat. Batshuayi is the most likely option but he has very little experience in playing alongside Lukaku.
58 minUnderstandably, Japan are playing with huge confidence now and are pinging the ball around like they believe they can win. Haraguchi's cross is headed behind by Witsel under pressure from Osako.
60 minIt seems Gareth can do no wrong at the moment, even when England aren't playing!
62 minMISS! This could be a key moment in this match. Meunier whips in a cross to the near post and Lukaku sends a glancing header wide with the whole goal gaping. That would have restored the faith in this Belgian side because previously they had looked a little lost after conceding the second.
64 minDe Bruyne is fighting for a second ball midway into his own half - that is not where Belgium need him now! Japan exchange a lovely one-two to release Inui down the right and his cross into the near post is turned away by Courtois, off the leg of Kagawa and behind safely (just) for a goal kick.
66 minSUBSTITUTION: Martinez has made a double change, bringing on Fellaini and Nacer Chadli for Carrasco and Mertens. That should allow De Bruyne to move further forward and also gives them even more of an aerial threat from set pieces. Good changes from Martinez, but is it too late?
68 minJapan are simply refusing to give Belgium any time on the ball. Their energy is unbelievable as Hasebe chases down Vertonghen and forces one of the world's best ball-playing centre-backs into a mistake.
69 minBLOCK! Outstanding block from Yoshida to dive in front of Lukaku who had turned Meunier's cross goalwards...
69 minThe Red Devils have one back and it comes from an unlikely source in Vertonghen, and in even more unlikely circumstances. The Spurs defender loops a header over Kawashima from the extreme left of the penalty area - questions will be asked of the Japan goalkeeper. It looked like Vertonghen was just returning the ball to the danger area but he generated so much power behind it, he could have meant it!
71 minJapan are straight back on the front foot and Kompany is lucky to get away with a blatant tug on Inui as he ran into the box. The Japan winger is actually penalised for a foul by the referee.
73 minBLOCK! Nagatomo this time is the Japan hero who dives in front of De Bruyne's 20-yard drive.
74 minFellaini does exactly what he was brought on to do as he powers a header down and through Kawashima to bring Belgium level. The build-up is all about Hazard though who twists his way past Sakai and delivers a wicked left-footed cross. All the momentum is with Belgium now. Can they get another?
76 minCHANCE! This has been a breathtaking second half and Japan nearly provide a fresh twist as Inui gets into the left-hand side of the box and has a shot from close range blocked by Alderweireld.
78 minWe have seen already that Belgium's new-found confidence could play into Japan's hands. The Red Devils are committing a lot of players forward now which leaves them open to the counter-attack.
80 minBelgium have two huge targets to aim at now in Lukaku and Fellaini. The striker is the target here from a cross from Chadli, who has been really lively since coming on, but Yoshida heads it against Lukaku and behind for a goal kick. Respite for Japan but there is lots more of that coming...
82 minSUBSTITUTIONS: Double change here from Japan - a case of fresh legs more than anything. Hotaru Yamaguchi and Keisuke Honda - one of the recent poster boys of Japanese football - are on for goalscorer Haraguchi and Shibasaki. Surely they would take extra time now?
84 minCHANCE! Honda makes a good run inside a congested penalty area and Kagawa picks out the pass. Honda tries to thrash home a left-footed shot by Kompany comes across to deflect it behind.
86 minSAVE! Big double save from Kawashima, who theatrically denies Chadli who jumps back to his feet to stand up a cross for Lukaku's header which the Japanese keeper tips over the crossbar.
88 minKawashima spills a 30-yard drive from Vertonghen and is lucky that Fellaini - going for the rebound - was offside.
90 minChadli dances his way into the box and it takes two defenders to stop him at the expense of a throw-in, which Vertonghen launches into the box but over Fellaini and Japan boot it to safety.
90+1 minSAVE! Courtois comes to the rescue after Witsel diverts a Nagatomo cross back towards his own goal, and it may have been sneaking inside the post. Japan still believe!
90+3 minSHOT! Honda sees his name up in lights, taking on a free kick which must have been 40 yards out. He gets it on target but Courtois comfortably pushes around his post.
90+4 minEuphoria for Belgium and heartbreak for Japan as Nacer Chadli sends his country through the the quarter-finals of the World Cup with the last kick of the game. It is so harsh on Japan but it is a goal worthy of winning any game, a swift counter from a Japan corner which Chadli finishes off from six yards out after Lukaku had dummied Meunier's cross. What a second half. What a comeback. What a World Cup!
9.03pmBelgium will face Brazil in the quarter-finals of the World Cup, but that only tells half the story. That is the first two-goal comeback in a World Cup knockout game since 1970, with Japan the unfortunate victims having done their country proud. But the Blue Samurai have hit their last-16 ceiling again.
9.05pmThat's it from me at the Rostov Arena. Relive another unbelievable game from this 2018 World Cup with our match report here, and be sure to rejoin us tomorrow for another last-16 double bill as Sweden take on Switzerland, and England face Colombia in the big one. Thanks for joining us this evening!