The Ghanaian striker was on target in the 65th to restore parity for Patrick Vieira’s side in a very tense game at Selhurst Park.
Ayew last goal for the club came in November 2020, but he had since been experiencing a long goal drought.
The 30-year-old’s strike against Southampton was his first goal in 43 Premier League matches and he expressed his relief after the game.
"It’s a relief I think. I knew it would come at some point because I’ve been working really hard for [a long] time,” Ayew told the BBC.
“I was happy for myself personally - for my confidence it is important - for my family, friends, people who have been supportive and especially the manager, who has been really supportive.”
He added: "Since the first day the manager came in he told me he has big faith in me and belief in me and I should keep on working hard and it will come.
“It may take long but at some point it will pay off and today it paid off. We’re all glad… Today there were negatives and positives but I think it was a good result."
Ayew would hope to score more consistently and carry his form into next year’s Africa Cup of Nations (AFCON) for Ghana.