The race for automatic promotion from the Championship took another twist as Sheffield United missed the chance to move back into the top two after being held to a 1-1 draw by Birmingham.
Neither side produced a standout performance for much of a pedestrian first half, but Blades wing-back Enda Stevens hammered a thunderous effort past Lee Camp to give the visitors the lead (38).
With their recent points deduction for breaching EFL financial regulations, a point would have greatly improved Garry Monk's side's chances of escaping relegation, and within four minutes they were back in the game after Michael Morrison prodded home from close range (42).
Birmingham: Camp (6), Colin (6), Morrison (8), Dean (7), Pedersen (6), G Gardner (6), Davis (6), Maghoma (5), Mahoney (6), Adams (6), Jutkiewicz (6)
Subs: Jota (6), C Gardner (n/a)
Sheffield United: Henderson (7), Basham (6), Egan (6), Cranie (6), Baldock (6), Norwood (7), Fleck (6), Stevens (7), Duffy (6), Sharp (5), McGoldrick (6)
Subs: Dowell (5), Madine (5)
Man of the match: Michael Morrison
The draw leaves Chris Wilder's men trailing second-placed Leeds by a point, while Birmingham are now six points clear of the bottom three with five games left to play.
With Leeds having regained second spot after a 2-0 win over Preston on Tuesday evening, the ball was back in the Blades' court as they prepared for the visit to St Andrew's.
Their slick passing game, though easy on the eye, failed to help them plot a route to goal for much of the first half, while goalkeeper Dean Henderson was forced to rapidly backpedal to bravely keep out Gary Gardner's angled shot.
However, seven minutes before the break, wing-back Stevens picked up Mark Duffy's short pass, stroked the ball out onto his left foot and thundered an unstoppable strike through the palms of Camp.
That said, the hosts, menacingly went about seeking an immediate reply and it took just three minutes and 38 seconds for the Blues to get back on level terms; the Blades couldn't deal with Gardner's header, allowing Morrison to poke home from close range.
Both Chris Wilder and Garry Monk made solitary changes to their sides for the Championship clash at St Andrew's.
Birmingham midfielder Maikel Kieftenbeld - who damaged his anterior cruciate ligament in the 1-0 win over Leeds at the weekend - was replaced by David Davis, while Martin Cranie took the place of Kieran Dowell in the Blades lineup.
Monk introduced Jota on the hour mark and the Spaniard immediately breathed new life into the game; his clever through ball to Che Adams was met with an excellent strike and equally as brilliant, acrobatic stop from Henderson.
Roared on by a sizeable away following, the Blades ramped up their efforts in the closing stages, but though they came close through headers from David McGoldrick and John Egan, the Blades were forced to settle for a share of the spoils.
Man of the match - Michael Morrison
Not only a great defensive performance, keeping opposing captain Billy Sharp's influence to an absolute minimum, Morrison scored a vitally important goal for the Blues and one that changes the face of the automatic promotion race.
He, alongside central defensive partner Harlee Dean, was at the heart of the resolute display from Garry Monk's men and it's quite clear why his manager is hoping to tie the 31-year-old down to an extended contract at St Andrew's.
Garry Monk: "If you look at the context of everything, who we are playing against, the game on Saturday and then again today, it's a really good point for ourselves. I thought we showed a huge amount of resilience today, we had a fantastic attitude and we knew it was going to be difficult playing against a team like Sheffield United.
"If you look at the last two games, taking four points considering who we are playing against, I think that's a fantastic effort by the players. I think we showed a great response going a goal down…and the scoreline was probably a fair reflection of the game."
Chris Wilder: "We went right to the end and that's what I said to the players, that we maybe lacked a touch of quality in the final third late on, but we went right to the end. It's a real difficult place to come and get a result as another team found out on Saturday. They are stubborn opposition…they bring Jota off the bench and Che [Adams] who has, obviously from his point of view, really improved.
"You look at the league table, we are a point behind with five games to go and there's no easy games in this division; I think everybody would've expected Norwich to absolutely cruise tonight. That's where it is - it's tight, it's always going to be competitive…but no doom and gloom from me, it's a fabulous position to be in."
Birmingham take on Paul Lambert's bottom-of-the-table Ipswich at Portman Road on Saturday, while Sheffield United host Millwall at Bramall Lane. Both fixtures get underway at 3pm.