Manchester United defender Chris Smalling admits he regrets being sent off in the derby at Manchester City earlier this season.

United boss Louis van Gaal branded Smalling "stupid" for a red card, during the first half of the derby against City.

"I was foolish, and it was a rush of blood," said Smalling.

"You learn more from yourself than from what managers and fans say. It's something I've not done too often and hopefully it won't happen again. I've learnt not to get caught up in these situations. I try not to clock up too many cards, but that was a moment of madness."