West Brom boss Ryan Mason urged his team to learn the lesson from Jayson Molumby's dismissal as they let a two-goal lead slip in their 3-2 defeat by Championship leaders Coventry City.
Molumby received his second yellow card of the game just four minutes into the second half at the CBS Arena after a brace by Aune Heggebo had put them on top.
"It was a lack of discipline in that moment (by Jayson), it's affected the result and it's something we need to learn from as a group," Mason told BBC WM Sport.
"We played a really good first half, created some excellent moments, showed good personality and quality as well, and scored two really good goals
"But at this level - and I think at any level - if you go down to 10 men then it's going to be very hard.