After City old boy Daniel Sturridge cancelled out Edin Dzeko's opener for the hosts, a 73rd-minute Steven Gerrard thunderbolt gave Liverpool a glimpse of victory, only for Sergio Aguero to level moments later.
While Liverpool can take heart from a bold display at the Etihad Stadium that followed their 2-2 draw at Arsenal in mid-week, City are left to contemplate the unenviable task of reeling in United.
"We didn't play well. In the last month we played well in all the games, but we were so nervous in this game and I don't know why," said City manager Roberto Mancini, who refused to concede defeat in the title race.
"Is the title race over? No. Seven or nine points (deficit) don't change. I think we can recover it," he said.
Liverpool took the game to City in the early stages, with Pablo Zabaleta sliding in to thwart Sturridge after he had rounded Joe Hart and Luis Suarez shooting wide, but it was the hosts who took the lead in the 23rd minute.
David Silva found James Milner motoring down the left flank and his low cross was turned home from close range by Dzeko. It was the Bosnian striker's 11th league goal of the campaign but he was to play an unwitting role in Liverpool's equaliser six minutes later.
Believing he had been fouled by Daniel Agger, Dzeko stayed down on the pitch but play continued and a Liverpool attack culminated in Sturridge beating Hart with a crisp low strike to peg back his former club.
Gerrard put Liverpool ahead with the kind of goal upon which he has built his reputation, chesting down a high ball 30 yards out and letting rip with a stunning half-volley that flashed past Hart into the bottom-left corner.
It was fitting reward for the visitors' enterprise, but a rush of blood to the head from Liverpool goalkeeper Pepe Reina helped Aguero to equalise just five minutes later. The Spaniard raced out to the left-hand edge of his area to challenge the City striker but Aguero neatly eluded him before brilliantly curving a shot into the empty net from a prohibitive angle.
"It should have been a win for ourselves," said Liverpool manager Brendan Rodgers. "I thought we played terrific and were the dominant team. We scored two wonderful goals and I am disappointed with the goals we conceded."
Earlier, Tottenham Hotspur lost Jermain Defoe to injury but won 1-0 at West Bromwich Albion through a fine Gareth Bale goal to bolster their push for Champions League qualification.
Emmanuel Adebayor's commitments with Togo at the Africa Cup of Nations have left Defoe as Spurs' only senior striker, but he had to go off in the 39th minute at The Hawthorns after appearing to twist his ankle.
Tottenham manager Andre Villas-Boas later revealed that Defoe had been withdrawn from England's squad for their friendly against Brazil on Wednesday.
Spurs were given a helping hand early in the second half when West Brom's Macedonian left-back Goran Popov, on loan from Dynamo Kiev, was shown a straight red card for spitting towards Spurs right-back Kyle Walker. The visitors made their numerical advantage count in the 67th minute as Bale took his tally for the season to 11 league goals with a vicious strike from just outside the 18-yard area.
On playing in a more central role, Bale told Sky Sports: "I enjoy it. It's a role that I'm learning season by season. "I've come in (from the wing) more often than in previous seasons and I enjoy it. It's a new experience for me, a chance to improve my game and add a new dimension."
Victory took Villas-Boas' side to within a point of third-placed Chelsea in the Premier League table, while West Brom stay in ninth place.
West Brom coach Steve Clarke said Popov would face punishment over his actions. "There are no excuses at all for Goran Popov, he has let everyone down," Clarke told the BBC. "It would be a strong case for him to receive disciplinary action, but it will be dealt with internally." – Sapa-AFP