Stoke City boss Mark Hughes has claimed that Manchester United's winning goal should not have stood during his side's 2-1 defeat at Old Trafford on Tuesday.
Juan Mata's free kick on the hour gave United the three points, but teammate Marcos Rojo looked to be in an offside position and interfering with play when the ball hit the net.
"We're disappointed with the second goal because we think it's offside," Hughes told Sky Sports News. "Those decisions have to go for you, certainly when you come to a ground like Old Trafford.
"You need the officials to get the key moments correct and I don't think you could argue that Rojo was interfering with play. He's trying to jump and it's missed his head by centimetres so he's clearly in an offside position because he's ahead of the ball."
The Potters continue their Premier League campaign on Saturday when they welcome Arsenal to the Britannia Stadium.