Only three points separate the two sides in the table ahead of the weekend's action, although both have been in less-than-convincing form of late.
It is an unsettled Manchester United which will greet Chelsea at Old Trafford on Sunday, with questions over the team's style, results and relationships in the dressing room lingering over their heads.
On paper, the improvement is clear to see; United are seven points and, crucially, four places better off than at the same stage of last season - the difference between sixth place and a runners-up spot.
Even the most ardent of United fans will have long since been resigned to finishing second behind Manchester City at best, with the gap between the local rivals now a whopping 16 points, but Mourinho's side still have a fight on their hands simply to finish in the top four.
A surprise 1-0 defeat to Newcastle United in their last Premier League game means that only four points now separate second from fifth, and with Liverpool and Tottenham Hotspur both in action before this match, things could get even tighter by the time United and Chelsea are underway.
The Red Devils have not lost back-to-back Premier League games all season, but should they suffer that fate this weekend then Chelsea would move level on points with them and, depending on results elsewhere, there could be few as two points separating the four teams vying for three Champions League places.
Mourinho's apparently broken relationship with Paul Pogba has dominated the headlines for United recently, with the France international having been dropped twice and subbed twice in his last four games for the club, although an injury did see him introduced early during Wednesday's Champions League goalless draw with Sevilla.
In many ways that match provided a neat microcosm of United's season; the result itself was decent enough and gives them the slight advantage heading into the second leg, but it was not done in 'the United way', and the toothlessness of a team that can call on the likes of Pogba, Romelu Lukaku, Alexis Sanchez and Juan Mata was once again alarming.
Mourinho has never been one to pay too much attention to his critics, though, and that is just as well considering one of his staunchest will be in the opposite dugout on Sunday.
The Portuguese has called for an end to the feud between himself and Conte, but this is by no means his first altercation with a rival manager and, handshake or no handshake, he is unlikely to let that sideshow distract him from the task in hand.
A return to winning ways would certainly help to calm the growing anxiety that the chasing pack are making up ground, and United's home advantage could ultimately prove to be the difference this weekend.
Only Man City have picked up more points in front of their fans in the Premier League so far this season, while in all competitions City are the only team to have beaten United at Old Trafford in their last 60 home games - a run which stretches back more than two years.
That includes a flawless record so far this calendar year of three wins without any goals conceded, while they also boast the best home defensive record in the top flight having conceded just five league goals at Old Trafford all season.
Two defeats from their last three league games home and away is a record which needs improving if they are to hang on to second place, though, and with Liverpool also on the horizon this could be a pivotal stage of United's campaign.
Recent Premier League form: WWWLWL
Recent form (all competitions): WLWLWD
Conte would be loath to admit this was the cause of Chelsea's recent form, but since the renewal of his spat with Mourinho, his side have definitely experienced a downturn in results.
Mourinho reignited the feud by appearing to refer to Conte as a "clown" in January, to which the Italian responded by suggesting that Mourinho may have "senile dementia".
Back-and-forth barbs including reference to Conte's past match-fixing ban and Mourinho's past "fake" behaviour followed, before the fiery war of words was put on ice.
Couple that timeline with that of Chelsea's results, and there is a clear correlation - be it coincidental or not. Since the beginning of January the Blues have won just four of their 13 matches across all competitions inside normal time, leaving them just one point clear of fifth-placed Tottenham Hotspur.
A 4-1 defeat at the hands of Watford at the start of this month left the Italian on the brink of the sack by all accounts, coming as it did just days after a 3-0 loss to Bournemouth, but Chelsea have since hit back with convincing wins over West Bromwich Albion and Hull City, before impressing during their 1-1 draw with Barcelona in midweek.
Conte labelled that display "very close to perfect", but the one mistake they made allowed Lionel Messi to score an away goal, leaving Chelsea to rue what might have been - although they have history of upsetting the odds to progress at Camp Nou.
The reigning Premier League champions cannot afford to dwell on what might have been, though, with Manchester United and Manchester City to come in their next two league games - both away from home.
Indeed, Conte's side are in the midst of a defining period of their season, with the next seven games in their current schedule seeing them face both Manchester clubs, three London derbies - including one against Tottenham Hotspur - the second leg against Barcelona and an FA Cup quarter-final with Leicester City.
Chelsea will begin that run looking for back-to-back league wins for the first time this calendar year, having only picked up maximum points from two of their six top-flight outings so far in 2018.
The Blues have also only won two of their last nine away games across all competitions, and they have lost their last two ahead of a run which sees them face United, City and Barcelona in their next three. Defeat on Sunday would condemn them to a third consecutive away loss for the first time since November 2015.
The speculation over Conte's future has not completely gone away either, and should they end this weekend outside the top four - something they can only guarantee will not happen with a win at Old Trafford - then more questions are sure to be raised regarding his position.
Recent Premier League form: DDWLLW
Recent form (all competitions): WLLWWD
All eyes will be on whether Pogba returns to the starting lineup for this match, having been dropped to the bench against Sevilla in midweek.
It was a sign from Mourinho that he doesn't trust the Frenchman in the big games, but injuries to Marouane Fellaini and Ander Herrera - whom he replaced in the first half on Wednesday - could force his hand.
Eric Bailly made his first appearance since early November in the FA Cup win over Huddersfield Town last weekend and would be a timely inclusion in the starting lineup with Phil Jones, Daley Blind and Marcos Rojo all sidelined and not expected to recover in time.
Mourinho may look to ease the Ivorian back into the team, though, while the match is also expected to come too soon for Zlatan Ibrahimovic despite his recent return to training.
Scott McTominay will be hopeful of keeping his place in the side, while Marcus Rashford, Anthony Martial and Jesse Lingard are among those pushing for a recall having started on the bench against Sevilla.
Lukaku will lead the line against his former club, but the Belgian is yet to register a single shot on target in matches against fellow top-six opposition this season and hasn't scored against any of the top eight teams.
Chelsea are unlikely to make many changes to their lineup from the draw with Barcelona, although Alvaro Morata - who scored the winning goal in the reverse fixture - is expected to be recalled.
That would likely see Pedro lose his place in the side as Eden Hazard drops back to his favoured wide role, with Willian's performance against Barcelona surely enough to earn him another start this weekend.
Gary Cahill is another who will be hoping for a recall and his experience could see him given the nod ahead of Andreas Christensen or Antonio Rudiger, although Chelsea defended well on the whole against the might of Barca's attack.
Man Utd possible starting lineup:
De Gea; Valencia, Smalling, Bailly, Young; McTominay, Matic, Pogba; Martial, Lukaku, Sanchez
Chelsea possible starting lineup:
Courtois; Azpilicueta, Christensen, Rudiger; Moses, Fabregas, Kante, Alonso; Wilian, Morata, Hazard
Head To Head
Chelsea have been Manchester United's bogey team in recent years, losing just one of their last 14 meetings with the Red Devils across all competitions.
That solitary defeat did come in the corresponding fixture last season, though, as goals from Rashford and Herrera sealed a 2-0 win for United - their first at home to Chelsea since 2011.
The Blues won the reverse contest earlier this season, though, with Morata scoring the only goal of the game 10 minutes into the second half of the November clash at Stamford Bridge.
We say: Man Utd 1-1 Chelsea
The big matches between top-six rivals have not disappointed so far this season, but this is one neither can really afford to lose. Defeat for Chelsea could see them playing catch-up in the top-four race while piling more pressure on the shoulders of Conte, whereas United really would be scrapping for Champions League football too if they were to lose.
That could result in a tentative affair, and we are going for a low-scoring draw.