Chelsea head coach Antonio Conte urged his team to forget about Premier League leaders Manchester City and focus on trying to catch United.
City's lead at the top was cut to five points by United on Tuesday, with Chelsea a further six points back ahead of hosting Swansea City.
Pep Guardiola's side have been flying atop the table with 12 wins from 13 matches, scoring 42 goals and conceding just eight.
Conte said Chelsea simply needed to focus on overtaking United, not high-flying City.
"We have to look at ourselves and not the others. Now our target must be to see the team that is before us. In this case, Manchester United," the Italian told UK newspapers.
"Our first target is to catch them up and if we are able to do this and then we can see the team who is staying before us. This must be our mentality and in every game we have to try to win and do our best. This must be the right mentality, winning mentality.
"If you leave Man City out of the table there is United and we are three points behind [before Jose Mourinho's men beat Watford 4-2].
"Man City is doing something incredible until now but we have to trust to continue to improve in our work in our team and try to do our best. This is the right way."
Chelsea are unbeaten in five league games, including a win over Manchester United and draw with Liverpool.
Conte said there were plenty of positives for his team after a poor start to the season.
"We are in November and trying to do our best. We have 11 points less than Manchester City but we have played all games against the other five top teams," he said.
"We are in the second round of the Champions League. We have to play the quarter-final of the Carabao Cup.
"For the problems that we had from the start of the season we are doing our best."
