Tottenham captain Hugo Lloris has questioned their bottle after Friday's defeat at West Ham.
Chelsea have the chance to take another big step towards the title when they take on Middlesbrough at Stamford Bridge on Monday night.
If they avoid defeat, they will end the season unbeaten at home, while they need two more points from United's visit and the trips to Leicester and Hull to seal their highest ever Premier League finish of second.
"With all the obstacles we have had this season the guys deserve a lot of credit", said manager Slaven Bilic, who has had to cope with continual speculation about his future. "We managed to bring it back to four points but after today, it's almost impossible, but we will give it everything for the last three games". Chelsea now need just six points from four remaining games to seal the title. "And today was a key moment and we couldn't show that thing. It will be a massive game anyway but playing against good opposition, it will be nice if we can pick up a win".
Manchester: David Silva returned from injury with a goal as Manchester City strengthened their Champions League qualification chances with a comfortable 5-0 win over Crystal Palace at the Etihad Stadium on Saturday.
"I am calm, disappointed of course because we missed an opportunity to reduce the gap on Chelsea".
Lanzini scored the only goal of the match in the loss, but Pochettino is not giving up until it is mathematically impossible to win.
"You all know now it is more hard to catch Chelsea but we need to try always until the end".
Spurs were looking lethargic at the Olympic Stadium when Manuel Lanzini punished them in the 65th minute by grabbing the only goal of the London derby.
A dejected Christian Eriksen of Tottenham Hotspur looks on as West Ham players celebrate their team's 1-0 victory.
What has proved costly for Tottenham are the dropped points in the opening months of the season. Tottenham is still set for a second consecutive season in the Champions League for the first time.
Tottenham's despair was in stark contrast to West Ham who not only put a huge dent in their local rivals' hopes of a first title since 1961, but also guaranteed their own safety.
"We deserved to win".