Chelsea boss Frank Lampard has warned his players to be cautious of the likes of Bruno Fernandes ahead of Sunday's FA Cup semi-final.
The Blues take on Manchester United with a place in the final against Arsenal or Manchester City at stake.
Ole Gunnar Solskjaer's men have had a series of VAR decisions go their way in recent weeks.
Fernandes won a penalty against Aston Villa despite replays showing he initiated contact with Ezri Konsa.
Lampard has warned his defenders to be on their guard at Wembley.
He said: "They have to be. Because when players of such high level, quality and speed of the Manchester United forwards travel quickly you have to move your feet and not dive in on them.
"You need to understand the qualities of the opposition, with players like that. Fernandes is very clever in his movement. We saw that at Aston Villa to make something feel like a penalty where maybe it even isn’t.
"As a player we can talk about VAR decisions and whether they’re right or wrong. But if a player is going to dangle a leg and not move their feet then you obviously do leave yourself open to penalties, VAR or no VAR."
United also benefitted from a favourable call against Crystal Palace when Victor Lindelof's challenge on Wilfried Zaha went unpunished shortly before Marcus Rashford put them head.
Lampard added: "The confusing thing about some of the recent ones, and the one on Thursday night, is that it’s a very, very clear and obvious decision that was wrong and didn’t get reviewed and changed. A few of those have happened and that is strange.
"I would like to think that with VAR you have to be level headed. Some might go against you or not. But we seem to be in a period where, in terms of Manchester United, they’ve got a few in their favour."
