"It was like slow motion really," he laughed.
"I put it in the net and did not know what to do. I couldn't remember how to celebrate because I had not scored for so long.
"But with the rain, it was the perfect weather for doing a slide, so that is what I went for."
If Giggs had trouble coming up with an appropriate reaction, it is little wonder his staggering list of achievements do not come readily to mind either.
When you first start to list them, starting with 10 titles, he looks slightly embarrassed, by the time you complete them, a record-equalling 758th Manchester United appearance and a goal, his 144th, to confirm the Red Devils' status as England's undisputed number one, he acknowledges it is impossible to play down.
"I am not going to play it down, I can't really," he said. "To equal someone like Sir Bobby Charlton is special.
"He is the embodiment of everything that Manchester United stands for. He has been watching me since I was 13 playing for Salford Boys and has seen me come through the youth team.
"To be level with someone like that, and win the championship and score a goal is fantastic."
But, ever the professional, Giggs allowed himself just the briefest of celebrations - at last night's player of the year function in front of hordes of adoring fans at Old Trafford - before focusing on the next challenge; beating Chelsea in the Champions League final.
"It has to be that way," he said. "You can't look back, you have to look forward."