"I felt quite sharp and the breathing will come back," he says.
He was involved in a certain amount of controversy when it became public that he had asked for a transfer in the aftermath of relegation, but he stresses:
"I have always said that I love playing football and when I do that I don't think about anything else; I just take it as it comes."
Jermain didn't make onto the scoresheet against the club for whom he spent such a sucessful loan spell in Harry Redknapp's reign, but he says:
"The fans know that every game I play for West Ham is 100% and I always want to do well; to be honest the fans weren't too bad tonight because I was thinking they would give me a bad reception and they didn't.
"I just love playing football and every game I play for West Ham I always try my heart out."
As for that transfer request, he says:
"To be honest I haven't even spoken about it or thought about it; I have just got on with it.
"No one has spoken to me and I have just got to get on with the football - that is all I want to do.
"To be honest I don't even know what is going on; I have spoken to the gaffer and everyone has acted normal.
"I could definitely be in a West Ham shirt next season and I was here tonight playing for West Ham.
"Even in training I want to score goals; it is not anything against the club or the fans - I am trying my best."