But the United boss admitted Greenwood knew he was now more under scrutiny than ever, having been sacked from England in disgrace last month.
Greenwood and Phil Foden have been sacked from Gareth Southgate’s England squad for breaking strict Covid-19 protocols by bringing two women into the team’s hotel in Iceland.
Solskjaer said: “I think Mason learned a hard lesson this summer, of course.
“It’s the reality that when you do well at Manchester United you will be in the spotlight, whether it’s good or bad.
“The more bad decisions there are, the more likely you are to be followed. When you play well, you just steer clear of this.
“But he’s never been a problem here in training, he’s training really well and I really love to see him develop. I’ve seen former United players talk about him and they don’t know what they’re talking about.
“We have a great track record, a tradition and a history of bringing our players through. It means from the start you pick up good habits, we trust you, you can express yourself.
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Ole Gunnar Solskjaer may have missed Jadon Sancho this summer, but he still made great strides in the transfer market with the arrival of Donny van de Beek, Alex Telles and Edinson Cavani.
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“Mason came through this program, he did it fantastic and he’s going to kick in I’m sure. He’s a very exciting boy to work with.
Asked if Greenwood, who has not been in United’s last two teams, had made a target with his off-field driving, Solskjaer said: “I’m not at all concerned about Mason who make himself a target.
“He’s a fantastic boy to work with. He’s never, ever late for training. He’s never a problem when he’s on the training ground.
“We have photographers outside the training ground every day so they can see it’s on time every day. He has a good family behind him, a good experience at the academy and he is a good coach. ”
Solskjaer claimed Greenwood missed the victories at Newcastle and PSG because the striker suffered from a ‘problem’.
However, yesterday the United boss said he was hopeful that Greenwood, who is due to start today, has recovered from his ‘illness’.
Solskjaer said: “I hope he is out of his illness and will be ready for this weekend. “