Grayson, who at least had the consolation of seeing his men complete 12 months undefeated in the league at Elland Road, said: "It was disappointing, but that's football. Last week we were on a high from the result at Manchester United and we were disappointed because we were below the standards we set ourselves, but give credit to Wycombe for the way they played.
"After the Lord Mayor's show is going to be the phrase that is bandied about, I'm sure, but these things happen.
"Wycombe came here without any fear and we had too many players below par. We didn't have our usual energy and quality."
Grayson included Jermaine Beckford in his starting line-up despite the 20-goal marksman's transfer request and the manager said: "Jermaine tried hard for the team and the crowd were fine towards him. He was part of a group of players who were below their best."