Managerless Middlesbrough will begin the post-Aitor Karanka era on Sunday when they take on top-four hopefuls Manchester United at the Riverside Stadium.
Steve Agnew will be in the dugout for the hosts as they look to give their survival hopes a boost, while Jose Mourinho's side could close the gap on the Champions League places to three points for a few hours at least.
Middlesbrough
It was Karanka's time working alongside Mourinho at Real Madrid that made him an attractive candidate for the Middlesbrough job three-and-a-half years ago, so being denied the opportunity to come up against his old friend for one final time in the role may add insult to injury for the Spaniard.
Only four Premier League managers had been in charge at their clubs for longer than Karanka before his sacking on Thursday and, while the suggestion from chairman Steve Gibson is that the decision was a mutual one, it will still irk Karanka that he was not given the chance to secure Boro's Premier League status having been the one who led them to it in the first place.
As Championship runners-up last season, Karanka's time in charge at the Riverside Stadium will be fondly remembered by many fans, despite numerous reports of fallouts with everyone from the players to the owners to the supporters themselves throughout his spell at the helm.
However, his ability to keep the club in the top flight had been increasingly questioned throughout what is now a 10-game winless run in the Premier League that has seen Boro pick up just four points from a possible 30 since Christmas.
It is the longest current winless run in the division, and leaves Boro 19th in the Premier League table, three points from safety and in danger of that gap growing considering the recent improvement of many teams around them.
Agnew's first assignment is a difficult one, but whether he, Nigel Pearson or anyone else is handed the role until the end of the season or beyond, the first question has to be simply: 'How are Middlesbrough going to get out of this mess?'
So often in such scenarios the first priority is to tighten up at the back, which is why Tony Pulis and Sam Allardyce - Crystal Palace permitting - have been so successful at steering teams away from danger. However, Boro have conceded just 30 goals in their 27 games this season - fewer than Liverpool and Arsenal and a tally that only four teams in the entire league can beat.
Unsurprisingly, then, the main problem is at the other end of field, where Boro have scored a league-low 19 goals all season - five fewer than bottom-placed Sunderland. Indeed, the Smoggies have not scored a league goal in their last four games and have only found the back of the net twice so far in 2017 - the lowest tally in Europe's top five leagues.
Boro have averaged the fewest shots on target per game, failed to score in more games than any other side and have won fewer matches than anyone else in the top flight this term, so fans will be hoping that whoever comes in at least brings with him a more expansive style of football.
In the short term, though, a draw may be the best Boro will be hoping for on Sunday and, considering these two sides have drawn more games than any other teams in the division this season, it is a realistic goal for the hosts too.
Boro have only lost one of their last five home games and held a free-scoring Everton side to a goalless draw at the Riverside last month, although only two teams have a worse record in front of their own fans this term.
With only 11 matches of the season left, every game is of vital importance for Middlesbrough now, but the players will know that an upcoming triple-header against Swansea City, Hull City and Burnley is likely to have a much bigger impact on their survival hopes than this game against United.
Recent form: LDLDLL
Recent form (all competitions): LDWLLL
Manchester United
It was Manchester opposition that ultimately brought Karanka's time at the Riverside Stadium to an end, and it is Manchester opposition that will kick the new era off on Sunday.
While Man City's FA Cup win over Boro was followed up by their exit from the Champions League, United suffered a reverse of those fortunes as the defence of their FA Cup crown came to an end at the hands of Chelsea on Monday before they scraped through to the Europa League quarter-finals at the expense of Rostov on Thursday.
The performance in that match at Old Trafford will not have been enough to convince fans that United are truly back on track following a dip in form, though, with a dominant display for the most part only translating to a 1-0 victory over the Russian mid-tablers - and that owed a lot to saves from Sergio Romero too.
Indeed, United have been off the boil since lifting the EFL Cup at Wembley last month, being held at home by 10-man Bournemouth in their last Premier League outing before a draw away to Rostov and the defeat to Chelsea.
Mourinho was keen to deflect attention away from those recent performances by launching his latest lamentable tirade against his side's fixture schedule, which sees United given the early kickoff on Sunday despite having been in action on Monday and Thursday already this week.
Those comments drew the anger of United legend Roy Keane, and while Mourinho was bemoaning his perceived number of "enemies" he may have created a few more in the Boro dressing room by suggesting that certain unnamed players were instrumental in getting Karanka sacked.
When it all comes down to it, though, Mourinho must above all focus on getting the results his side need to chase down Liverpool in fourth place. Winning the Europa League is an increasingly plausible means of securing Champions League football, but the top four is not out of their grasp either - they trail Liverpool by six points and have two games in hand over their fierce rivals, who face Man City later on Sunday.
Dropped points against a Middlesbrough side in turmoil will be another major blow to that goal, but United have won five and lost none of their last seven matches against promoted teams and have kept five clean sheets in the process.
In many ways it looks like a perfect match for United. Their current 17-game unbeaten streak is the longest in the Premier League this season, stretching back to October, and they are taking on a team with the longest current winless run in the division.
United also share the league's best defensive record away from home against a Middlesbrough side who have scored fewer than anyone else in front of their own fans, and only Man City and Chelsea have amassed more points on the road than the Red Devils while only two have amassed fewer at home than Boro.
However, for a side who have been regularly criticised - from the inside and out - for their failure to turn chances into goals this season, the biggest challenge for a United team who will be without suspended top-scorer Zlatan Ibrahimovic could once again be breaking their opponents down, and few are quite as stubborn at the back as Boro.
Recent form: DDDWWD
Recent form (all competitions): WWDDLW
Team News
Ibrahimovic will serve the second of his three-match domestic ban for elbowing Bournemouth defender Tyrone Mings this weekend, leaving Mourinho with a selection dilemma up front.
The Swede is the club's top-scorer with 26 goals across all competitions this season, and he has attempted almost a quarter of their shots in the Premier League, so they are big boots to fill.
However, Anthony Martial remains a doubt for the game and captain Wayne Rooney's availability is unclear after he missed the last two games with a knee injury sustained in training.
Mourinho will also be without the suspended Ander Herrera following his controversial red card against Chelsea on Monday, while Paul Pogba is sidelined with the hamstring injury he sustained against Rostov.
Daley Blind was also forced off early on Thursday after picking up a knock to the head, and he is a doubt along with outcasts Luke Shaw and Bastian Schweinsteiger.
Middlesbrough, meanwhile, are hopeful that Bernardo Espinosa and Rudy Gestede will overcome the hamstring injuries they picked up against Man City last week, although Bernardo is understood to be further away from fitness than Gestede.
The hosts can also welcome Adlene Guedioura back after he was cup-tied for the last outing, but defensive trio Calum Chambers (foot), Daniel Ayala (hamstring) and George Friend (calf) remain out.
Middlesbrough possible starting lineup:
Valdes; Barragan, Bernardo, Gibson, Fabio; Leadbitter, De Roon, Clayton; Ramirez, Negredo, Traore
Man Utd possible starting lineup:
De Gea; Valencia, Bailly, Smalling, Rojo; Carrick, Fellaini, Lingard, Mata, Mkhitaryan; Rashford
Head To Head
Middlesbrough's only triumph over United in their last 12 meetings across all competitions came on penalties in the League Cup in 2015, with the Red Devils winning seven and drawing four of the remaining 11.
United have scored in all of their 14 away games against Boro in the Premier League - their longest active streak against a single opponent - with their last Riverside blank in the league coming in January 1989.
The reverse fixture on New Year's Eve saw Martial and Pogba rescue United with quickfire goals in the final five minutes as they came from behind to win 2-1 and extend their unbeaten run against Boro in the Premier League to eight games.
We say: Middlesbrough 0-1 Manchester United
This may not be a classic, with Boro likely to shut up shop and United struggling to break teams down at the moment. Middlesbrough's next defeat will be their 1,000th in the top flight, while United's next win will see them become the first club to record 600 Premier League victories, and we can see both landmarks being reached on Sunday.