Jose Mourinho claimed Chelsea scored their winner against Manchester United on Sunday in the "only period" they were dominating the game.
Alvaro Morata rose high to plant Cesar Azpilicueta's cross beyond David De Gea and hand Chelsea a third Stamford Bridge win over Manchester United since Mourinho joined the Red Devils.
In a surprisingly open affair, United had opportunities to level late on, with substitute Marouane Fellaini, on his return from injury, taking a high ball down and drawing a fine low save from Chelsea goalkeeper Thibaut Courtois.
But Chelsea held on and closed to within a point of United in the Premier League standings and nine behind runaway favourites for the crown Manchester City.
Red Devils boss Jose Mourinho said: "I think they scored the goal in the only period where they were on top of the game."
Mourinho was once again left to lament the absence of several players for United's recent run of fixtures after his second-placed side slipped eight points behind runaway league leaders Manchester City.
He added: "We are second, we are not fifth or sixth or seventh or eighth, so we have 18 teams in a more difficult position than we have. Eight points is eight points.
"We went through a very difficult phase with probably the most important matches - Tottenham, Liverpool, Chelsea - without important players. I don't like to speak and it's not after a defeat that I'm going to speak but it is obvious through a difficult period with limitations."
The Portuguese confirmed he did not shake hands with opposite number Antonio Conte at the final whistle, adding: "He disappeared so I shook to his assistants."
Additional reporting by Press Association