Steven Gerrard gave Liverpool the lead two minutes into the second half but they were pegged back nine minutes later when Liam Ridgewell headed the home side level and visiting fans were left exasperated after Spain striker Fernando Torres was substituted.
Liverpool remain in sixth place with 55 points from 33 games played with Tottenham Hotspur in fifth place on 58 from 32 and Manchester City, who are now favourites to grab fourth after a 6-1 thrashing of Burnley on Saturday, on 59 from 32.
West Ham United earned a precious point in their battle to avoid relegation, drawing 2-2 at Everton thanks to a late equaliser by Brazilian striker Ilan, while Wigan Athletic remain in trouble after squandering a first-half lead to lose 2-1 at Fulham.
Gianfranco Zola's side, who halted a run of six consecutive defeats despite twice trailing and Mido missing a penalty, have 28 points, one ahead of third from bottom Hull City who have a game in hand. Wigan have 31 points.
Liverpool manager Rafael Benitez claimed tiredness was the reason he withdrew leading scorer Torres at Birmingham with 25 minutes to go - a decision which left the striker, who has netted 18 league goals this season, shaking his head.
"He was exhausted, we played 60 minutes with 10 players the other day," Benitez, whose side will try to overturn a 2-1 deficit at home to Benfica in the Europa League on Thursday, told the BBC.
"(David) Ngog was good for us because he was a pair of fresh legs. His movement was good for the team.
"We had Ryan Babel ready, Dirk Kuyt and Maxi Rodriguez so we had enough people in attack."
Ngog failed to convert two glorious chances to put Liverpool back in front shortly after replacing Torres, adding to the disquiet amongst the visiting fans.
After a dull first half Gerrard ended his recent goal famine to shoot Liverpool in front with a pinpoint finish but the visitors were guilty of poor defending as the unmarked Ridgewell equalised, bundling in a James McFadden cross at the far post.
"It was a silly goal, when you concede, it is not the best but in this way it's the worst," added Benitez. "The reaction of the team was good, we were attacking and creating a lot of chances. We are disappointed because it was a good performance."
Liverpool joined Manchester United, Chelsea, Arsenal, Manchester City and Tottenham Hotspur in failing to win at Birmingham this season and with just five games left, three of them away, they are now long shots to claim fourth place.
