After commenting this week on the importance of individual performances, United's new owner and chairman, Eddie Thompson, will have watched with despair at how his troops performed in this game - one in which they will want to forget.
The SPL leaders began in commanding form and, after enjoying such dominance in midfield, it was only a matter of time before they went ahead.
Surprisingly it did not come until the 22nd minute. Following a controversial foul by Danny Griffin on Fernando Ricksen, Mikel Arteta curled a free-kick for Lorenzo Amoruso to out-jump the United defence and nod into the corner from 12 yards.
The Tangerines almost equalised immediately. Stephen O'Donnell's cross over the Rangers defence allowed Steven Thompson to run in but a brilliant spread-eagled stop from Stefan Klos stopped a certain goal.
The game dropped a gear until five minutes before the break when Rangers almost doubled their lead. From an acute angled free-kick, Arteta almost caught out Paul Gallacher. Expecting a cross, the keeper threw himself back to tip the ball off the underside of bar.
But it was only short-term relief as, in the first minute of injury time, the second goal came.
Captain Barry Ferguson laid a long ball to Ronald de Boer and the Dutchman, criticised in midweek by his former manager, beat Cummings on the byline before returning the compliment and rolling the ball into his captain's path for the midfielder to fire high into the net off the underside of the bar from 14 yards.
The second half continued in a similar vein although the hosts stemmed the relentless pressure to construct some attacking play themselves. Nevertheless, it was always Rangers who looked more likely to score.
Injury forced de Boer to depart earlier than he hoped to be replaced by Claudio Caniggia.
The substitution proved to be a rewarding one as six minutes later he crossed for Shota Arveladze to net Rangers' final goal from close range. The striker's first shot was well saved by Gallacher but the Georgian followed up to bundle the ball over the line to seal a convincing victory