The French international was sent off after a challenge on Andy Carroll just moments after picking up a yellow card for booting the ball away.
Alan Pardew: "Moussa was frustrated he has not got the free-kick in the box, and then just lost his mind a bit, with kicking the ball away and then in the next incident is just a minute after.
"It is not like Moussa, he has been outstanding for us.
"He has to learn from this, but he is not a malicious player, although having seen it on the replay, it does not look good."
"We just lacked the clinical touch we have had in recent weeks.
"We did not really create the great moment we needed, although we got into some good positions, we could not find the great pass we needed, which we have done in recent weeks.
"The goal we conceded was disappointing, having defended superbly against a team who put us under a lot of pressure.
"You kind of sensed that one goal was going to be important for both teams.
"Unfortunately today, we have just come up short."