The Liverpool captain proved the man for the occasion, scoring twice from the spot and missing a third penalty to inspire his side's first win at Old Trafford in seven attempts in all competitions as Brendan Rodgers' men moved ahead of Manchester City into second and within four points of leaders Chelsea with a game in hand.
Nemanja Vidic was sent off for two yellow cards, receiving his second when he brought down Daniel Sturridge for Liverpool's third penalty, before Luis Suarez added further gloss to the scoreline with six minutes remaining.
An under-par performance coupled with a further dent to United's European aspirations piles further misery on David Moyes and the Premier League champions, as their Merseyside rivals remain firmly in the hunt for a first league title since the 1989-90 campaign.
The first of Gerrard's converted penalties ensured Liverpool went in ahead at the break, after Rafael used his hand to deny Suarez an opportunity on goal.
While referee Mark Clattenburg chose not to show the defender a second yellow card, the hosts found themselves behind at half-time and Moyes was left to rue another costly foul early in the second half.
Phil Jones brought down Joe Allen and, when Clattenburg pointed to the spot, Gerrard made no mistake.
Gerrard then missed the chance for a hat-trick of penalties when Vidic felled Sturridge, the Liverpool skipper crashing his effort against the post. Suarez, though, did add a third for Liverpool six minutes from time as the visitors clinched a vital three points.
Sturridge was quick to showcase his movement if not his finishing prowess early on when he fired wide after just two minutes before Liverpool appeals for a penalty were waved away.
Suarez appeared aggrieved after feeling the clumsy tackles of Jones and then Marouane Fellaini in quick succession warranted spot-kicks, but Clattenburg had other ideas.
Other than Liverpool's early pressing, chances were few and far between in the opening exchanges - Robin van Persie's blocked effort the best United could produce before Sturridge spurned the opportunity to test David de Gea when he failed to fashion a clean strike on goal after turning Vidic.
Allen did force the Spaniard into a save shortly after, capitalising on Vidic's error to get an effort away on goal, before Rafael handled inside the area to give Liverpool a penalty after Suarez cut in from the left wing.
Gerrard kept his cool to send De Gea the wrong way and hand the visitors a 34th-minute lead - while Rafael will perhaps feel a touch fortunate not to have been given a second yellow card, having already been cautioned for a foul on the Liverpool skipper.
United finished the half on top, Wayne Rooney first seeing a shot saved by Simon Mignolet before the follow-up was well blocked by Martin Skrtel, but the hosts made the worst possible start to the second half when Jones bundled into Allen, with Gerrard registering his 10th Premier League goal of the season with another penalty.
Gerrard was denied a hat-trick when he struck the post from the spot 12 minutes from time, but the victory was complete when Suarez latched on to Sturridge's through-ball to register his 25th league goal of the campaign.
