Manchester United are the strongest team in the Premier League on a player-by-player basis, according to Chelsea head coach Maurizio Sarri.

Chelsea welcome United to Stamford Bridge on Saturday as Premier League action returns following the international break, and Sarri believes his side face a daunting task.

The Italian's comments may come as a surprise to some given the Red Devils sit eighth in the table and trail unbeaten trio Manchester City, Liverpool and Chelsea by seven points.

So indifferent has United's form been in 2018-19 there had even been speculation Jose Mourinho could lose his job at Old Trafford, but Sarri is convinced this weekend's opponents are the best in the division.

"They are a strong team, maybe that player by player they are the best in Premier League," Sarri told a media conference.

"At the moment City is better as a team, but player-by-player they [United] are very strong."

Sarri also had praise for his counterpart Mourinho, who will make another return to the ground where he won three Premier League titles across two separate spells.

He added: "We are talking about a coach that has won everything, everywhere, so I think you have to respect him.

"I think that I have to respect him, and I think you [the media] all have to respect him.

"I think that he is a very good coach, one of the best in the world."

Meanwhile, Mourinho insists returning to Stamford Bridge will not be different to any other game in United's schedule, but he concedes he will not celebrate should his team cause an upset.

"For me it's another game," said the United boss. "Would I celebrate like crazy my team's goal or victory at Stamford Bridge? I don't think so. 

"I think I'd try to control myself and respect the stadium and the supporters that were my supporters and what was my stadium for many years. 

"To do that [celebrate crazily] it would [mean] I completely lost my emotional control, which isn't easy. I want to do well for my team, my supporters. I'm 100 per cent Manchester United, there's no space for anything else but respect for the stadium and people who were my friends."

Chelsea head into Saturday's clash only trailing leaders City on goal difference after eight matches, but Sarri still expects them to improve in the coming weeks.

"I'm very happy with the results but we need to improve, and we can improve because we have had no time to work [together]," he said.

"I had eight players at the beginning of August, then we play every three days, so it is difficult to work, to improve the team, to improve the players.

"In the future we can improve, and we need to. To improve the performance, and in the defensive phase, we're giving too many opportunities to the opponents."