Jose Mourinho was left bemused by Frank Lampard's decision to leave experienced players out in favour of youngsters in Chelsea's 4-0 thrashing at the hands of Manchester United.

Lampard opted to leave the experienced N'Golo Kante, Olivier Giroud and Marcos Alonso on the bench at Old Trafford, with Mason Mount, Tammy Abraham and Andreas Christensen among the starters.

Although Chelsea competed well for large periods, they ultimately lost 4-0 thanks to a brace from Marcus Rashford and strikes from Anthony Martial and debutant Daniel James.

Mourinho, who has often in his career been criticised for a lack of faith in young players, believes Lampard was wrong to leave out some of his older heads, adamant Kante could have started the match if he was fit enough to play the latter stages after a hamstring injury.

"I understand if Willian is injured not to play him, but if Willian is not injured and is just late, I do not understand why he is not here," Mourinho, a former manager of Lampard's, said as a pundit on Sky Sports.

"To play 30 minutes you do not need to be fit. If Kante can play 35 minutes [he played 17 minutes], he can play the game, even if he lasts one hour.

"It's difficult to say, because I am not there. My feeling is they had a possibility to play with a team with more know-how.

"Alonso was on the bench, Kante was on the bench, Giroud was on the bench. Even if this is not the United that used to scare people, this is Manchester United.

"A little bit of experience would fit well with the team. You look at the performances of Mount, Abraham and even Christensen. For matches of this dimension, you need a little bit more."