Cristiano Ronaldo was seen remonstrating from the bench during his side's Champions League defeat to Young Boys on Tuesday, and Rio Ferdinand wasn't impressed.
The ex-United defender criticised head coach Ole Gunnar Solskjaer for how he handled the incident.
"If I'm the manager, I've got to be honest, I'm telling him to sit down," Ferdinand said on BT Sport after the match.
"I get it. You know, with Cristiano people go, 'Oh it's bravado, it's for the fans'. He's just a passionate guy. He wants to win, he's desperate to win, and he can't hold it in.
"If that means he has to go up there and stand next to the manager, shouting instructions etc etc, so be it."
Solskjaer has hit back at Ferdinand for the comments, however, saying he doesn't know what he's talking about.
"Rio, again you know, sometimes he comments on things he doesn't really know," Solskjaer said.
"It should have been a yellow card for the boy when he brought down Nemanja (Matic). Both Bruno (Fernandes) and Cristiano, as competitive as they are, suddenly I had them on my shoulder.
"They were there for a brief spell and shouted to the referee. That was the aggravation of getting a few bad decisions against us.
"But then Cristiano sat down and Bruno sat down. We know that there is only one man allowed in that technical area and that's either me or Michael Carrick or Mike Phelan or Kieran McKenna who is up there."