West Ham manager David Moyes wants calm heads but not “vanilla players” in their Europa Conference League quarter-final against Gent on Thursday.
Aaron Cresswell also saw red, with Declan Rice suspended for confronting the officials in the tunnel.
“We have to learn where we can draw the line,” said Moyes.
“Emotions are something you never know what’s going to happen. Looking back I can understand it, we were right up against it on occasions, but we’ve got to make sure we are better disciplined, calmer.
“But we still want the players to be emotional, we want them to understand what it means, we want them to be motivated and eager to impress.
“We don’t want vanilla players who are going to go around and not tackle, challenge, run hard, be competitive. You need players who are going to do all those things.”
West Ham have had a difficult season in the Premier League, currently sitting 14th, just three points clear of the relegation zone.
However, they have won all eight of their games in the Europa Conference League and go into the last eight as the bookmakers’ favourites.
“I’d love to give the supporters another couple of nights like we did last season and I’d truly like to go further if we can,” said Moyes.
“I’ve got big respect for Gent but I would do for all the teams we play.
“We’ve got no divine right to be getting through, we’re going to have to work very hard for it, we’re going to have to play well.”