Ole Gunnar Solskjaer suggested the weather conditions, a bobbly pitch and the Europa League ball contributed to Manchester United's disappointing draw away to Club Brugge.
Anthony Martial struck an away goal to cancel out Emmanuel Bonaventure Dennis' opener and give United a slight advantage ahead of next week's return leg at Old Trafford.
Dennis capitalised on Sergio Romero misjudging a goal-kick from opposite number Simon Mignolet to put Brugge ahead, but Solskjaer felt conditions, the pitch and the ball all had an impact.
"It was a difficult game against a well-organised team in difficult conditions," he told a news conference.
"I don't think it was one of the best games that anyone's seen.
"We were a bit sloppy, concentration-wise, and the conditions, with the pitch and ball, made it hard.
"You can ask any of the players, that ball does not help when you want to play football.
"It's just different and difficult to play with, but it's the same for the two teams of course. It's light – you should get one and try it."
Brugge coach Philippe Clement rejected Solskjaer's complaint, though, and claimed Romero could have been dismissed in the second minute for a clumsy challenge on Dennis.
"We get the balls from UEFA, so it's not our ball," Clement told reporters. "In the Europa League games, it's the same balls, so I don't see a problem with that.
"For me, it's a clear penalty if I see the images, and in some countries, it's a red card. If you go with two feet forward against the leg of somebody, it's a red card.
"All the circumstances need to go your way if you're going to beat United, and tonight we didn't get that."