The Ghanaian lasted the entire duration, his won foul providing the opportunity for Gylfi Sigurdsson to curl home a free-kick for the Swans' equalizer in the 1-1 draw.
Wayne Rooney had put United in front from the spot.
“I felt we deserved to win," Ayew said according to his club's official website.
“We played better than them, but that is an encouraging sign.
“For our confidence that performance will really help.”
With the season at the homestretch, Swansea are trapped in the relegation zone, sitting third from bottom on the log.
“We have to take that [confidence] into the next three games. We have to stay positive,” Ayew said.
“They are three massive games for us, but we are fighting as much as we can.”
The Ghana international, who joined Swansea from Aston Villa in January, has so far made 11 league appearances involving six starts.
The former Marseille man is still chasing his first goal for Paul Clement's outfit.