Zaha had given Palace a first-half lead at St Mary's, but was sent off late on after picking up two yellow cards in a minute, with James Ward-Prowse having earlier equalised.
The Ivory Coast international lashed out at Ward-Prowse, who was also on the scoresheet in the game, to be booked before applauding referee Andre Marriner, leading to his second yellow card.
Zaha, 26, showed remorse on social media after the game suggesting that he was pleased that the sending off didn't cost his side a point, while also vowing to learn from his actions.
"All I can do is apologise to the team and the fans for my red card tonight because I could have cost us today," he wrote on Twitter.
"I will learn from it for sure."
Palace manager Roy Hodgson was frustrated by the red card, but said the referee had no choice but to give Zaha his second yellow.
"It's disappointing that the player who perhaps provided some of the best entertainment during the 90 minutes with his performance was consistently fouled throughout the game [and] wasn't able to contain his frustration with that consistent fouling," Hodgson said.
"Protests over a foul which is not given which probably should have been, but then once he applauds the referee's decision to give him a yellow card the referee, under the rules of the game and the instructions they are given, he's got no option but to send him off.
"So, there's not much one can say about it."
The 1-1 draw saw both Palace and Southampton pick up a valuable point in their fight for Premier League survival as they both moved four points clear of the relegation zone.