Lukaku sustained an ankle injury in last month’s victory over Arsenal. Photo: Phil Noble/Reuters

LONDON – Manchester United have concerns about the fitness of Anthony Martial and Romelu Lukaku ahead of Saturday’s FA Cup final against Chelsea, manager Jose Mourinho has said.

France international Martial, who has scored 11 goals in all competitions, missed United’s 1-0 win over Watford on Sunday due to a knee injury.

Lukaku, United’s leading scorer in the league with 16, sustained an ankle injury in last month’s victory over Arsenal and travelled back to Belgium to recover.

“Anthony, I have to wait a bit for more. It’s his knee,” Mourinho told reporters. “He was injured in the Friday training session and on Saturday he couldn’t train. He had treatment in the morning at the training ground and he stayed away.

“I’m waiting for the doctor but when it’s impossible to play today, I have my doubts (for the Cup final). Let’s wait and see, also for Romelu.”

An ankle injury may rule Romelu Lukaku out of Saturday’s FA Cup final. Photo: Nigel Roddis/EPA

Chelsea manager Antonio Conte has warned his team that they must improve on their toothless display in Sunday’s Premier League defeat by Newcastle United when the London outfit take on Manchester United.

Chelsea, who harboured an outside chance of a top-four spot heading into the final league fixture of the season, were overwhelmed at St James’ Park, falling to a 3-0 defeat by 10th-placed Newcastle.

The loss, coupled with Liverpool’s 4-0 home win over Brighton, ended Chelsea’s hopes of securing Champions League football for next season as Conte’s defending champions finished five points behind the Merseysiders in fifth.

“For the next game, for sure we must change. If we think we can play a game like this in the final of the FA Cup then we don’t have a chance,” Conte told reporters as he looked ahead to Saturday’s Wembley showdown.

“Newcastle showed great desire and fight and outplayed us but we didn’t play a good game. We have six days to change our approach and desire and will to fight... Our fans deserve more than Sunday.”

The Italian, who led Chelsea to the league title in his debut season at Stamford Bridge, said his team’s poor campaign was a “big disappointment”.