Ayew struck as the Foxes came from 2-0 down to win 2-3 at St Mary's.
"Massive three points, back-to-back wins especially after the international break is not easy," he said.
"We did well, we fought, we pushed them and pushed ourselves as well and got the three points. Onto the next one.
"I just think there was more desire, more intent, more positivity in our mindset. That's what made a difference."
On staying on the edge of the box for his goal, Ayew also stated: "It was just natural instinct. Luckily the ball came, it wasn't easy but I managed to score. We're all happy and hopefully, there is more to come.
"Everyone was happy and that's what we play football for, these kinds of moments.
"We just need to stay humble because we were losing 2-0 so all is not perfect. It's not going to be every weekend like this, it's going to be tough. But we have a quality group, we believe in ourselves, we believe in our manager. We are going to give our best for the club.
"We are a group of 25 or 26 players and everyone will play a part this season. It's not only 11 players and we all need to stay positive and work hard for the team."