West Brom defender Jonas Olsson admits he 'should know better' after his rash challenge on Javier Hernandez earned him a second booking and his marching orders at Manchester United.
The Swedish centre-back was dismissed by referee Lee Probert in the 66th minute at Old Trafford having landed two bookings in 17 minutes with the Baggies 1-0 down.
United went on to beat 10-man Albion 2-0 as Wayne Rooney followed up his opener with a second-half penalty after Keith Andrews fouled Ashley Young in the area.
Olsson's red card marked West Brom's first of the season and was the 29-year-old's only Premier League dismissal since arriving at The Hawthorns in 2008.
The stopper, who will now miss next weekend's trip to Wigan as he serves a one-match suspension, held his hands up after the sending off and admits the late tackle on Hernandez was "stupid".
"The second booking was a stupid challenge from me and I should know better," Olsson told West Brom's official website.
"I thought maybe the first yellow was a bit hard. But I think I'm experienced enough to think about my decision-making with the second challenge.
"I'm very disappointed on that personal level and disappointed that we lost the game after such a good run lately.
"We managed to stay in the game but my sending off was a blow for us.
"I'm very disappointed but you have to learn from this."
Sunday's Old Trafford defeat ended a run of three successive wins for West Brom, who slipped to 14th in the table.
Olsson is determined to atone for his sending off when he returns from suspension, which is likely to be when the Baggies host Newcastle on 25th March.
He added: "I don't like missing games.
"When you have a bad game or a red card, or whatever, you want to redeem yourself as quickly as possible."