After securing a rare victory at Manchester United last weekend, the Eagles had just about enough to win 1-0 against a Villa side who played with a man short for over half an hour following the sending off of Trezeguet.
Palace had failed to score in three of their last four home games and the Selhurst Park crowd would have been getting nervous after a number of wasted chances preceded Ayew's goal – the forward following up on his strike at Old Trafford with another crucial effort here.
Both sides reverted to their last league line-ups after resting a host of players in the Carabao Cup, but Dean Smith's Villa were unable to build on their impressive win over Everton.
Wesley had an early chance to add to his goal in that victory last time out but shot tamely at Vicente Guaita in the Palace goal inside the opening minute.
Moments later and the £22million summer signing almost got lucky as John McGinn's cross cannoned off him, with Guaita again able to hold possession.
The hosts then took control of possession but did not create a clear chance of note until the midway point of the half, Villa full-back Frederic Guilbert gifting possession to Jeffrey Schlupp, whose cross was turned just over the crossbar by James McArthur.
Tom Heaton held a deflected Schlupp strike as Palace began to exert more pressure on the Villa defence, Ayew just inches away from turning home a McArthur cross from the next attack.
Heaton then pushed a low Luka Milivojevic free-kick behind as Palace's familiar frustrations in front of their own supporters continued.
The second half started as the first had ended, Palace again creating chances as Villa's defence presented them with the ball, with Bjorn Engels guilty of being caught in possession leading to Cheikhou Kouyate firing wide.
Palace's chances of picking up the three points were boosted as Trezeguet was shown his second yellow card for upending Zaha on 54 minutes, having also been booked just before the interval.
Milivojevic once again stung the palms of Heaton but opportunities were coming at a premium, Ayew shooting wide from distance as frustrations started to grow at Selhurst Park.
But he would soon be celebrating his second goal in a week, collecting a pass from Schlupp before bundling past Tyrone Mings and Grealish and then finishing with aplomb.
Mings, having been selected in the England squad for the first time earlier in the week, would have felt he could have done more but the relief around the majority of the stadium was clear – with manager Roy Hodgson having Andros Townsend and Christian Benteke readied to come on, only to send them back to the bench.
The game ended in contentious fashion, Grealish galloping forward with the ball before hitting the deck on the edge of the Palace box.
The Villa skipper did not appeal for a penalty and the ball broke for Lansbury to fire in, only for Friend to blow his whistle and show a yellow card to Grealish, who was incensed with the decision.