Ole Gunnar Solskjaer might have restored positivity at Manchester United, but Chris Smalling insists the caretaker manager has a "nasty side".
United won 10 and drew one of their first 11 games after the former striker succeeded Jose Mourinho in December, with his unbeaten run coming to an end against Paris Saint-Germain in the Champions League on Tuesday.
Solskjaer has won praise both for improving United's standard on the pitch and for lifting the morale around Old Trafford following a tough final few months under Mourinho.
But while Smalling says he is "a joy to play under", he claims Solskjaer is not afraid to use a stricter approach when needed.
"I think he has got that sort of nasty side," Smalling told MUTV. "I think every manager has that, the so-called hairdryer treatment when things need a little turnaround. A manager has to have all different sides covered. He's a joy to play under and he's great."
United face Chelsea in the FA Cup on Monday knowing that the competition represents their best chance of ending the season with silverware.
Smalling is confident of a positive result at Stamford Bridge, particularly given they were moments away from a 2-1 win in the league this season before Ross Barkley struck an injury-time equaliser.
"This year, we're making sure we get a trophy and, on Monday, we'll be going all for it," he said.
"The record at Chelsea, you're right, we've not had too many good results there but I thought, earlier in the season, we were so close to winning until the last dying seconds. In general, we played quite well there, so let's kick on and improve on that performance.
"The fact it's Monday night as well means it's got the whole world watching. They'll be looking to improve on last weekend's result [at Manchester City], as we will [after PSG], so it's a big game all around."
Smalling feels primed to play his part for the rest of the season after admitting he rushed back from a broken toe too quickly in December.
"I'm fully healed from the broken toe now. It was good to be available again on Saturday [against Fulham] and get that game under my belt," he said.
"It's just about managing my next game and getting back up to match fitness. Hopefully, I'll be available for all the games until the end of the season.
"Through the Fulham and Arsenal [home] games, I had injections and then I had more injections for the Liverpool game [at Anfield] but it made the injury worse. So, then it was a case of getting it right and getting back as soon as I can but, first and foremost, making sure it was right."