Jordan Ayew scored midway through the first half, with Daniel James thinking he'd rescued a point for Manchester United with his curling equaliser late on.
However, Patrick van Aanholt scored past the goalkeeper at the near post winning the game for Crystal Palace in stoppage time.
Back in the Premier League, Palace beat Aston Villa 1–0, but the game turned toxic after a decision by referee Kevin Friend to disallow a late equaliser by Henri Lansbury.
Palace took the lead early in the second half thanks to a fortunate own goal from Leander Dendoncker, but could not hold on due to Diogo Jota’s last-gasp equaliser.
Palace started October strongly, where despite going 1–0 down to Sebastien Haller’s goal for West Ham United, a Luka Milivojević penalty levelled the game.
After an international break, Palace were back at Selhurst Park against Manchester City where goals from Gabriel Jesus and David Silva downed the high-spirited Eagles.