They belted out You Will Never Walk Alone in unison with their counterparts in England.
They moaned, groaned, cursed and swore with fellow-Reds fans worldwide when, against the run of play, Carlos Tevez tucked home what was to be United's winner on 43 minutes.
Over at The Crab Shack, the United faithful, numbering about 100, had gathered to cheer on their team with the League summit in sight.
But the importance of the match was driven home by Liverpool die-hard fan Mohamed Rasuul. 'It's more about pride than the championship,' said the 28-year-old events executive.
The battle for bragging rights between the clubs with the two largest fan followings in Singapore meant both venues were places of high tension.
Even the TV commentator seemed to know what it felt like, aptly describing the Anfield atmosphere as 'suffocating' - exactly what it was at the Hard Rock.
Fortunately, despite the tension, peace prevailed at the Hard Rock, unlike at The Crab Shack.
While high-fives and fist pumps were the order of the day as the Red Devils fans celebrated victory over their bitter rivals, there was a brief moment when emotions threatened to get the better of some.
A heated argument broke out, allegedly over a spilt drink, but a timely intervention by some cool-headed fans diffused the situation within minutes.
Still, it was not enough to sour the United fans' ecstasy. 'The title is ours to lose,' declared Ryan Bauer, 26.
But many Reds fans remained defiant. As Garfield Lim, 39, said: 'It's not over.'
JEROME SEOW