Mané was dismissed after a clash with Erik Pieters in added time of Saints’ 2-1 victory at Britannia Stadium last Saturday.
With video evidence making it clear that he had not used his arm and that the pair had instead just clashed heads, the Football Association upheld an appeal from Saints, meaning the forward is available for tomorrow’s home game against Liverpool.
"I was very confident when I saw the clips about the situation of the red card, because it wasn't, and finally the FA took the right decision to suspend it and Sadio's available, and that's also good news,” Koeman told Southampton’s official YouTube channel
With Mané having not scored since the 6-1 Capital One Cup home defeat to Liverpool in December, Koeman hopes the successful appeal could give him a bit of a lift.
"That will be good, but that's football,” he said. “You're never the whole season on the same level.
“Sometimes you're struggling a little bit about confidence, about scoring, and you know if strikers don't score maybe sometimes they have more doubts about themselves than they need to be normally.
“Ok, that's part of the team and he's working hard, he's doing well Sadio and he needs confidence, but he will be the Sadio that we know always.”