Jack Grealish says he was "shattered" after Manchester City's 5-1 win over Club Brugge.
The Englishman, signed from Aston Villa in the summer, played the full 90 minutes int he emphatic victory.
Agbonlahor told talkSPORT: "If I was Ole (Gunnar Solskjaer, Manchester United manager) in the hotel now, I'd be showing them the City game from last night.
"Look, they've got a a £100million player and all these superstars hunting the goalkeeper down, pressing all over the pitch, and leaving everything on the field.
"I spoke to Jack last night and he was shattered from the game.
"They are not just luxury players who can only do it when they've got the ball, they are pressing everyone.
"Manchester United should be doing that in every game they play."