Usain Bolt has told Ole Gunnar Solskjaer to find his mean streak if he wants to be at Manchester United long-term.
The Olympic legend is an avid Red Devils fan and has previously asked to play for them.
Bolt was asked for his assessment of a United side who currently sit second in the Premier League.
Solskjaer currently holds the reins at Old Trafford but has so far been unable to deliver any silverware.
The Norwegian has a relatively modest managerial CV and Bolt thinks he needs to harden up if he is to be a success.
“If he changes - he's too nice," Bolt told CNN when quizzed on whether Solskjaer should be in charge long-term.
“That's the only thing I can say, he's too nice. He never really says anything bad about any player, even if they don't play good and that's the only thing.
"But if he changes and really pressures the players, you know what I mean, calls them out sometimes when they really didn't put their all into it, then I feel like he should stay because he is cool and the fans love him.”
Solskjaer inherited an expensively assembled squad that had been pieced together across several managerial tenures.
He has begun to establish an identity and a recruitment strategy during his three years.
Bolt though singled out a midfield regular - Fred - for particular criticism and questioned Edinson Cavani's lack of minutes.
“I think Fred should not be in the midfield," he added.
"I think he is lacking so much. He works hard, but he's lacking passing and he gives away a lot of cheap fouls in bad areas.
"We definitely need more strikers, somebody that's really a pure striker.
“I think [Edinson] Cavani needs to play more. I definitely feel like as long as he's fit, he should be on the field, you know what I mean.
"Overall I think we need to just pressure all the players. I feel like they're so comfortable now because they know they're going to start.
“If you're sure of your spot, then you don't play as hard as you should. So it's just one of those things I feel needs to change and we'll be fine.”