The Hammers boss typically deflected the praise towards his team on the greatest day of his short managerial career so far, as he beamed: "I'm obviously very proud of the players, it was a stunning performance throughout the 90 minutes.
"I was very fortunate to play here many times and I never came away with a victory.
"So to bring a team here as a manager and come away with a win is special. It's definitely my best day in management."
As well as securing three vital Premiership points, the victory was also a tactical triumph for Glenn.
While many will automatically view the result as a repeat of last season's smash-and-grab FA Cup victory, anyone present yesterday would have to admit that the Hammers fully deserved their win, outplaying the hosts in the first half and restricting the likes of Scholes, Yorke, Solskjaer, Cole and Beckham to only a handful of half-chances after the break.
Said Glenn: "I thought we matched them on the passing stakes - in the first 45 minutes we had as much of the ball as they did, and we limited them to very few chances.
"We knew we would come under more pressure in the second half but we withstood that. They threw on big gun substitutes like Beckham, Fortune and Cole - after starting with 11 big guns in the first place - but the players defended bravely and on the few times we were breached, we had an England goalkeeper in superb form.
"I asked our MD Paul Aldridge if that performance was similar to the victory in the FA Cup last season, because I wasn't up here for that one, and he felt that today's performance was even better over 90 minutes, because we took the game to Manchester United and weren't under the cosh."
While David James was the popular choice as man of the match after continually denying the United attack, Glenn praised all 11 men as heroes and reserved special mention for his young England starlets.
"They were all heroes out there today but I have to mention Joe Cole and Michael Carrick, two 20-year-olds who were marauding out there today against Keane, Butt, Scholes and Beckham. I thought they were amazing.
"Young Jermain was also fantastic, but we're not going to place too much upon his shoulders. Hype isn't going to help his career. I've been patient with him and I will continue to be patient with him. Hopefully one day he'll thank me because I'm sure he will have a long and successful career in the game."
Our Chadwell Heath training ground will certainly be a very happy place this week but, added Glenn, also a serious one as the players look forward to another extremely tough Premiership fixture against London rivals Arsenal.
Glenn concluded: "The boys always train well, they're always bubbling, and there will probably be a bit more sparkle and bubble this week.
We won't be getting carried away, just working as hard as possible so that we can really look forward to a big game next Saturday against Arsenal, who have the best away record in the Premiership."