Manchester United's victory opens up a 10-point gap between the Red Devils in third place and sixth-placed Chelsea, with only 15 points left to play for this season.

The top five in the Premier League will qualify for the Champions League next season.

But a fourth consecutive league defeat leaves Chelsea's chances of being back among Europe's elite next season in tatters and piles pressure on Liam Rosenior just over three months into his reign.

Chelsea once again bemoaned the lack of a clinical striker as they failed to break down a makeshift United defence ravaged by injury and suspension.

Michael Carrick was forced to name a backline featuring three full-backs and 19-year-old Ayden Heaven.

But they held out to boost the former England's midfielder's case to get the job at Old Trafford beyond the end of this season.

Chelsea were missing their top scorer Joao Pedro through injury and one-time United target Liam Delap failed to take his chance to shine up front.

Rosenior recalled Enzo Fernandez after the Argentine was given a two-game suspension by the Blues for suggesting he would be open to a summer move to Real Madrid.

Fernandez started with a point to prove and came agonisingly close to the opener when he curled inches wide.

United looked rusty in a 2-1 defeat to Leeds on Monday in their first action for three and a half weeks.

But Carrick's men repaired the damage done to their chances of returning to the Champions League next season.

Cunha provided a precise finish to open the scoring two minutes before the break from Bruno Fernandes' 18th Premier League assist of the season.

Chelsea improved after the break but failed to prevent another damaging defeat that leaves Rosenior's role in doubt heading into next season.

Delap crashed a header against the woodwork and Noussair Mazraoui turned a dangerous cross onto his own bar under pressure from Wesley Fofana.

Moises Caicedo, fresh from signing a new seven-year contract, also came close to rescuing a point for the hosts.

But the final whistle was met by a chorus of boos at full-time with the Club World Cup winners looking resigned to Europa League football at best next term.