Eden Hazard has named Manchester United as Chelsea's main rivals for the Premier League title.
Antonio Conte's side moved nine points clear at the top of the table following their 1-1 draw with Liverpool at Anfield on Tuesday.
United, by contrast, have endured mixed form in the top flight under former Chelsea boss Jose Mourinho and are 15 points adrift of the leaders in sixth place, although they have a game in hand.
Chelsea take on third-placed Arsenal on Saturday and, speaking ahead of that encounter, Hazard has identified the Gunners and - specifically - United as the biggest threat to his side's title chances.
"I think Arsenal and Manchester United," he told Sky Sports when asked who he considers to be Chelsea's main challengers.
"United had a bad first part of the season and I think for a couple of games now, they played well. They drew against Stoke City but they have good players and the squad is very good. The manager is good, so they will be second or third.
"Tottenham also are strong. We lost there, but for me it is more Manchester United. They are more experienced. That is my opinion, maybe I'm wrong."
Hazard enjoyed a superb 2014-15 season under Mourinho as Chelsea claimed the title, but his standards dipped markedly last season before the former Real Madrid boss left the club in December 2015.
The Belgium international has recaptured some of his best form in Conte's 3-4-3 system this term and he has credited the manager's meticulous approach to training as a key factor behind those performances.
"In tactics and training we do more with Conte," he said. "We work a lot of tactical positions and we know exactly what we have to do on the pitch, where I have to go and where the defenders have to go.
"We know exactly what to do. With Mourinho, he put in a system but we didn't work lots. We know what to do because we play football, but maybe the automatisms [sic] were a little bit different.
"With Mourinho, Nemanja Matic was behind me in the season when we won the title and sometimes I stayed in front and Matic did the job.
"With Conte it's different. I close more inside because Marcos Alonso is there as a wing-back. I just need to be ready to counter-attack if we get the ball."