Assombalonga missed a penalty with the scoreline at 2-0 but made amends for his blunder by netting Forest's third in the 69th minute.
Find out how the action unfolded with Sports Mole's text commentary below.
Hello and welcome to our live text coverage of the Championship clash between Nottingham Forest and Ipswich Town at the City Ground. What a vital game this is for the hosts, who could be relegated to League One if they fail to better Blackburn Rovers' result at Brentford.
We'll provide you with an overview of who is in danger of the drop on the final day in a moment. First up, team news...
FOREST XI: Smith, Lichaj, Worrall, Mancienna, Mills, Osborn, Vaughan, Cohen, Carayol, Assombalonga, Ward
IPSWICH XI: Bialkowski, Spence, Chambers, Berra, Kenlock, Ward, Skuse, Huws, Rowe, Samuel, Sears
Let's start with the hosts, who have made two changes from last weekend's potentially damaging defeat to QPR. Daniel Pinillos is replaced at the back by Matt Mills and Jamie Ward is drafted in to replace Ben Brereton.
Mark Warburton has gone for a 4-3-3 formation with Britt Assombalonga spearheading the Forest attack and David Vaughan in a holding midfield role. Striker Zach Clough passed a late fitness test to land a spot on the bench.
Visitors Ipswich Town have also made two changes this afternoon and they are enforced ones. Rowe and Samuel come in for the injured Lawrence and McGoldrick, while promising youngster Flynn Downes is named on the bench for the first time.
Forest must better Blackburn's result at Brentford this afternoon or face the prospect of life in League One. Both sides head into the match on 48 points, with Warburton's side out of the bottom three by virtue of having a superior goal difference by one.
Tiny margins separate the teams ahead of kickoff, but that won't matter if Blackburn lose today. Championship status is very much Forest's to lose. You can see how the table looks going into this match here.
As you can see from the standings, Harry Redknapp's Birmingham City could be the ones relegated if both Forest and Blackburn pick up points. They travel to Bristol City on the final day and a draw simply won't do if the other two avoid defeat, as their goal difference is the worst of the bunch.
So what are Forest's chances today? History is on their side in this fixture since they haven't lost at home to Ipswich in 11 matches. They've also failed to score in only one of their last 10 home games.
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Offset that against the fact that only Aston Villa and Rotherham United have scored fewer away goals than Ipswich this season and a Forest result is sounding like a safe bet. However, it's worth pointing out that the Reds have lost their last three final-day home fixtures.
Ipswich have little to play for beyond pride and the prospect of moving up one place in the final standings. Mathematically, they could move up two if they overturn a minus-seven goal difference on Barnsley in 14th place.
Pre-match quotes from both camps coming up...
MICK MCCARTHY: "It's a game we need to really compete in, and if we don't, we'll get turned over."
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MARK WARBURTON: "You can't go to a group of players and say 'be committed' and not commit yourself." (via BBC Sport)
That Warburton quote came from his pre-match press conference in response to questions regarding his future as Forest boss. The former Rangers man is adamant he intends to stay on if the club goes down.
PREDICTION! I think that whatever happens at the City Ground this afternoon, Blackburn Rovers are the ones who will go down. They've been poor all season due to on and off-the-field turmoil and I don't see them bettering Forest's result today, nor do I see Ipswich getting anything here when there's so much at stake for the hosts. I'm going with a 2-0 win for Warburton's men.
The two teams are heading out on the pitch now. Will Nottingham Forest still be a Championship club by 2pm today? Stay tuned to find out...
KICKOFF! Forest get us underway at a packed-out, sun-drenched City Ground. The atmosphere is electric here, but will the home faithful still be in such good voice 90 minutes from now?
There's an early chance for Forest as a Jamie Ward strike from the edge of the box fizzes wide of the far post. It wouldn't have counted as Britt Assombalonga was in an offside position, but good energy from the hosts right from kickoff.
There's a nervy moment for Forest as Jordan Smith almost fumbles a cross from Danny Rowe. The ball came in at pace from wide on the right and proves too hot to handle for Smith initially, but he quickly recovers and gets both hands on it.
It's Ipswich who have settled into the match in the opening stages. They're forcing Forest to sit deep, but the Reds have just applied some pressure of their own as Assombalona chases a long ball down, forcing Bialkowski to race off his line and make the interception.
SAVE! It's our first clear-cut chance of the afternoon and it falls Ipswich's way as Ward unleashes a vicious drive, forcing Smith to save to his right, parrying the ball away at full stretch.
UPDATE! This is not the news Forest will want to hear. Blackburn have taken the lead at Brentford and that pushes the Reds into the drop zone as things stand. You can find out more here.
Here's how they stack up following that Blackburn goal. Look away, Forest fans.
SUBSTITUTION: The hits just keep on coming for Forest. They have been forced into a change as Mustapha Carayol goes off injured to be replaced by Zach Clough. I think he will join Assombalonga up front with the Reds switching to a 4-4-2.
UPDATE! Blackburn have gone two up at Brentford and that removes the goal difference variable. Nothing short of a win will do for Forest as things stand. Meanwhile, Birmingham have just taken the lead at Bristol City! That would be enough to keep the Blues up on goal difference.
Forest are struggling to break Ipswich down at the moment. The Tractor Boys are winning the battle in the midfield but the hosts almost found a way through as Clough gains possession inside the box, only to be dispossessed by Berra's well-timed tackle. Forest need a goal - we cannot stress that enough!
Even if Forest win here, there's a possibility they could go down on goal difference given that this is how we stand...
There are still no signs of them getting a stranglehold on this match. Long balls forward towards Assombalonga are proving ineffective for the hosts, who have spent much of the match in their own half, being pushed onto the back foot by an Ipswich side that is using a packed midfield to their advantage.
Forest press their opponents as Osborn's long ball picks out Assombalonga in the box. Berra does enough to put off the big striker and force him wide. Assombalonga makes it to the byline and attempts to play a pass across the face of goal but Bialkowski gathers comfortably.
Good defending from Osborn, who ventures deep to dispossess Sears on the flank. Forest are allowing Ipswich to get in behind them far too much. And since they aren't creating a lot going forward, Warburton's men are living dangerously at the moment.
Credit to Ipswich. They are defending in numbers when required and winning the midfield battle. Mick McCarthy appears to have gotten his tactics right by packing out the centre of the park. They're also looking dangerous along both channels via Sears and Rowe.
CHANCE! There's a great chance for Forest as Assombalonga whips a swift cross into the area for Lichaj to take on the volley, but the American can't keep his shot down. It was hearts in mouths for the home fans there!
Berra is having a cracking game for the Tractor Boys and there's a good battle going on between him and Assombalonga. He's just gotten the better of the Forest striker there, beating him to a long ball into the box.
CROSSBAR! Ipswich have hit the woodwork, but it actually goes down as a magnificent save from Smith! Samuel gains possession inside the area and shoots on the turn, his effort taking a deflection off Mancienne along the way. Smith is forced to think on his feet and his reaction stop turns the ball onto the crossbar! Samuel got so much power behind that. What a brilliant stop!
Smith keeps Forest's survival hopes alive, but it isn't looking great for them given that Blackburn and Birmingham are both winning... BUT THEY HAVE A LIFELINE NOW!
PENALTY TO FOREST!
GOAL! Nottingham Forest 1-0 Ipswich Town (Britt Assombalona, pen)
The City Ground goes bonkers as Assombalona fires Forest in front with a confident penalty, driven into the top corner. It was awarded after Ward was bundled over in the box by Bialkowski and comes against the run of play, but the home fans do not care one jot!
Forest are out of the drop zone on goals scored, but they're living dangerously. Berra heads an Ipswich corner over the bar and thousands of hearts skip a beat around the City Ground!
There will be two minutes of stoppage time at the City Ground, and both of them are certain to be nervy.
HALF TIME! Nottingham Forest 1-0 Ipswich Town
Nottingham Forest are on course to retain their Championship status... but only just. Britt Assombalonga's penalty has them out of the drop zone on goals scored and they're very much reliant on Blackburn's result at Brentford.
With Rovers two goals to the good and Birmingham also in front at Bristol City, it's imperative that Forest don't concede. Ideally, they need to score more since Blackburn extending their lead at Griffin Park could put survival out of their hands.
That won't prove easy since Ipswich have been the stronger team and created the better chances. Moments before Assombalona fired Forest in front from the spot, Samuel tested Smith in the Forest goal with a vicious shot on the turn, the keeper pushing the strike against the woodwork.
The two teams are heading back out onto the pitch and Ipswich make a change at the break, throwing on Emmanuel for Kenlock.
KICKOFF: The Tractor Boys get the match back underway.
There's a half-chance for Ipswich as Rowe curls an effort towards goal from outside the box. It's straight at Smith, but any Ipswich attack is going to send Forest nerves into overdrive, given that a goal for the Tractor Boys could send them down as things stand.
Such fine margins are keeping Forest out of the drop zone. Another goal for Blackburn would take them out of the bottom three, as would an Ipswich equaliser!
Good pressure from Forest as Assombalonga uses his strength to force the ball into the six yard box. He attempts to pull the trigger and it takes a combination of Samuel and Berra to foil him. Solid defending from Ipswich there.
Forest play a corner short and David Vaughan takes a touch before letting fly from 25 yards, his effort sailing into the stand. That attack wasn't up to much but the hosts have looked much brighter in the second half. They are actually getting up in Ipswich's faces now.
UPDATE! The pendulum swings in Forest's favour as Brentford have pulled one back against Blackburn. Read more here.
GOAL! Nottingham Forest 2-0 Ipswich Town (Chris Cohen)
The City Ground is bouncing now because Championship survival is within Forest's grasp! They double their lead through captain Chris Cohen, who bends a strike into the corner from 25 yards, beating Bialkowski with the help of a deflection.
Things are really looking up for Forest now. Cohen's deflected strike gives them a goal difference of -11 versus Blackburn's -13. Rovers could become the first former Premier League winners to drop into the third tier!
On the balance of play in the second half, Forest absolutely deserve this lead. Ipswich are having trouble getting on the ball now and the Reds just keep on pressing. The home side look hungry for goals!
Almost another moment for the home fans to savour as Osborn's low cross fizzes across the face of goal with no takers... BUT IT'S ANOTHER PENALTY TO FOREST!
PENALTY MISSED! Assombalonga steps up hoping to bury his second penalty. He goes for power again but Bialkowski meets it with a wonderful save to his left and pushes it over the bar. The pen was awarded after Emmanuel brought down Ward, earning the Ipswich man a yellow card.
IPSWICH SUB: Sears is replaced by Moore for the Tractor Boys.
GOAL! Nottingham Forest 3-0 Ipswich Town (Britt Assombalonga)
A day which began with relegation nerves becomes one of celebration for Forest as Assombalonga's 14th of the season puts them on the brink of survival! The big striker cuts inside the area, uses his strength to ward off two Ipswich defenders and fires into the roof of the net from a tight angle to make amends for his earlier penalty miss. I think you're forgiven, Britt!
CHANCE! What a fantastic attacking performance this has been from Forest in the second half! They just won't let up. Ward collects a searching ball from Assombalonga inside the box and plays a return pass to the striker, who shoots first time, his effort straight at Bialkowski.
Here's a reminder of how the table stands. Blackburn need a minor mathematical miracle to stay up now...
FOREST SUB: Brereton comes on for Jamie Ward, who leaves the park as a hero after playing a starring role this afternoon. He won both of Forest's penalties and has supplied plenty of service for Assombalonga. Warburton gives him a warm embrace on the touchline.
IPSWICH SUB: Ipswich make a change and it's Webster replacing Berra, who has been the Tractor Boys' best player today.
UPDATE! There's a fresh development at Brentford where Blackburn have extended their lead from the penalty spot. As things stand they are still going down and can no longer rely on a favour from Ipswich. They need Birmingham to concede at Bristol City.
FOREST SUB: Youngster Matty Cash comes on for Chris Cohen, another Forest player to be given a hero's reception as he leave the park. It was his goal that filled the stadium with the belief that Championship football will be played at the City Ground next season.
Forest still playing with the same energy which has carried them through this second period, but there's a break in play as Osborn goes off injured. The Reds will have to play out the final five minutes with 10 men.
There will be five minutes of stoppage time, but the Forest fans have started the party already.
Forest look content to allow Ipswich time on the ball in the dying stages and Ward gets his head to a cross inside the box. It's charged down by Mills and scrambled clear. This is looking like a clean sheet for Forest.
FULL TIME: Nottingham Forest 3-0 Ipswich Town
NOTTINGHAM FOREST AVOID RELEGATION TO LEAGUE ONE
Sensational scenes at the City Ground where scores of Forest fans have invaded the pitch. This is one for them to savour as the Reds beat the drop on the final day in emphatic fashion. A blistering second-half display has seen them demolish sorry Ipswich and maintain their Championship status.
Full-time whistles have sounded around the country and it's Blackburn who drop into the third tier due to Birmingham's victory at Bristol City.
And at the other end of the table, Newcastle United's victory over Barnsley has secured the Championship title for them as Brighton could only draw at Aston Villa.
Confirmation of how it stands at the bottom after the final round of fixtures.
And that's all we have timed for here but stick with Sports Mole for thorough coverage of the rest of today's big matches, as well as the fallout from the final day of the Championship. Many thanks for reading.