MANCHESTER -- Manchester United boss Jose Mourinho has said Anthony Martial's upturn in form this season is because the forward is playing with a smile on his face.
Mourinho questioned Martial last season and accused the 21-year-old of failing to capitalise on opportunities to impress.
The France international is locked in a battle with Marcus Rashford to start on the left of Mourinho's front three this season, but he has still scored four goals in seven games, including one in a man-of-the-match performance against Burton Albion in the Carabao Cup on Wednesday.
Mourinho told a news conference at Carrington on Friday: "I see a great improvement in the person, in the mood, in the face, in the body language -- if you want just a word, in the happiness.
"He's a happy guy, he's working extremely well. He starts matches, he tries to do well. He goes from the bench, even it is for 10 minutes like in the last match at home, he tries to enjoy and try to give something in these extra minutes.
"I am very pleased with his attitude overall and then it's easier to play well."
United face Southampton at St Mary's on Saturday looking to extend their unbeaten start to the Premier League season.
Mourinho will be without Paul Pogba, who is still recovering from the hamstring injury he picked up against Basel in the Champions League.
The midfielder was due to undergo more scans this week but the United manager has admitted he still has "no idea" how long he will spend on the sidelines.
Marouane Fellaini or Ander Herrera are in line to deputise against Southampton.
Mourinho said: "Again, it is a great opportunity for other players to play. I am not going to cry or be counting the days for Paul to be back, not at all. Until then, I trust my people."