Mavericks guard Darrell Armstrong was so happy his beloved Washington Redskins beat the Dallas Cowboys that he grabbed a microphone before Sunday night's game against the Minnesota Timberwolves and hollered, "How 'bout those Redskins!"

It's going to cost him $1,000.

Dallas coach Avery Johnson announced the fine during his postgame news conference and team owner Mark Cuban later verified it was legit, much to the chagrin of a disbelieving Armstrong. The money will all go to charity, with Johnson saying the Cowboys would decide the recipient.

The Redskins wrapped up a 35-7 victory over the Cowboys shortly before the Mavericks left the locker room to play the Timberwolves.