Manchester United boss Jose Mourinho has admitted that both Marouane Fellaini and Ander Herrera could miss Saturday's Premier League clash with Watford at Vicarage Road.

Fellaini impressed in United's 2-0 win over Burnley before the international break, but the midfielder missed Belgium's recent two matches with a back problem.

Herrera, meanwhile, is struggling with an ankle problem suffered in training, and Mourinho has conceded that both could miss the game in London as United look to make it back-to-back Premier League wins.

"Fellaini is a doubt. Ander Herrera is a doubt - he had one little problem in one ankle in training during the week, so he's a doubt," Mourinho told reporters during his weekly press conference.

Saturday will be the 31st meeting between Watford and United in all competitions. United have won 20 of the previous 30, suffering just five defeats. The Red Devils have also been victorious in nine of the 10 Premier League matches between the two teams.