UNITED 1 (Becchio 60), BIRMINGHAM CITY 1 (Elliott 32)
Leeds: Ashdown Lees Pearce Tate (Somma 79) Drury (Byram 46) White Brown Norris Hall (Diouf 46) McCormack Becchio. Subs: Kenny Peltier Varney Pugh.
Birmingham: Doyle, Caldwell, Davies, Packwood (Hancox 67), Robinson, Morrison, Burke, Elliott, Redmond, Reilly, Gomis. Subs: Butland, Ibanez, Hales, Gordon, Henry-Francis, Gnahore.
Referee: C Foy
The build-up to the game had been dogged by a virus sweeping through the Elland Road camp, its highest profile victim being United manager Neil Warnock who was absent from proceedings.
First team coach Ronnie Jepson was the man in charge from the dug-out with assistant manager Mick Jones watching from his usual vantage point in the stands.
One of the six team changes for Leeds was always on the cards, Jamie Ashdown coming in for Paddy Kenny as per the previous cup matches, and he made a good early save from Ravel Morrison.
United went close shortly before the quarter-hour when Jason Pearce did well to get on the end of a Ross McCormack free-kick, but his header came back off the upright.
It was actually quite an entertaining start with the game flowing from one end to the other. Both sides were looking to attack and both were looking to break quickly from their own half.
But the visitors went ahead after 33 minutes when Wade Elliott found space to have a strike from distance and his shot flew into the top corner.
It was a real opportunist strike, but one which was to ensure the visitors had the upper hand going into the break.
United made two changes at the break, Sam Byram and El-Hadji Diouf joining the fray, and the second period started in similar fashion to the first with both sides looking to get forward.
Ashdown and Tom Lees combined well to deny Birmingham on one occasion while another attempt from the visitors was over the bar.
Leeds were back in it on the hour-mark though when David Norris did well to guide the ball through to Luciano Becchio, and the striker made no mistake in slotting home his 19th goal of the season.
The visitors had a great chance to restore their advantage on 70 minutes when Nathan Redmond escaped the clutches of the Leeds defence, but his shot was off target.
With 11 minutes left on the clock, Davide Somma replaced Tate as United's final substitution.
The final 10 minutes offered little in the way of meaningful chances as the game appeared to be heading towards a replay, but Becchio did go close with a header in the first minute of stoppage time.
The replay will take place at Birmingham on Tuesday January 15 (7.45pm).