Manchester United manager Jose Mourinho has warned Anthony Martial that he must start taking his chances in the first-team.

Martial, 20, joined United on transfer deadline day last summer, making an immediate impact with a superb debut goal against arch-rivals Liverpool. While his side enjoyed a disappointing league campaign where they finished fifth, the France international was their shining light, scoring 17 goals in his first season in English football.

Under Mourinho however, he has struggled, scoring just twice this term and starting just nine games from a possible 19. Mourinho insists that like many members of the United squad, Martial is still adjusting to a new managerial approach very different to that of former boss Louis van Gaal. But after being dropped from the squad that eased to a 4-0 win over Feyenoord on Thursday, the former Monaco starlet has been warned he cannot keep wasting opportunities that come his way.

"First of all, the way the team played last season was very different – I'm not saying better or worse, just different," Mourinho told a press conference ahead of Sunday's Premier League clash with West Ham United.

"Probably Anthony was feeling more comfortable playing that way, at that intensity, at that rhythm of the ball – possession and ball circulation. So he probably needs some time." Mourinho also pointed out that there was plenty of competition for the attacking roles in his team, with several players hungry to impress.

"We have Mkhitaryan, Lingard, Depay, Mata, Rashford and Martial – these are the positions where we have more options," the boss said.

"You have one opportunity, maybe two or three. If you don't bite, somebody comes and takes the meat."

Henrikh Mkhitaryan's thrilling performance in that comfortable win over Feyenoord in the Europa League poses another threat to Martial's chances. Having previously started just one game all season – one where he was hauled off at half-time – the Armenia international provided a scintillating display that saw him scoop the man of the match award.

"He just needs now to replicate this kind of performance in the Premier League," Mourinho said of Mkhitaryan. "The Premier League is different – he needs one more step. Obviously now confidence levels are higher.

"This performance gives him the right to believe that he can play the next match again and he needs to replicate this kind of performance in the Premier League with more physicality and more aggression."