FA Cup - Late drama sends Bolton to Wembley
The Korean substitute nodded in from close range to settle a rumbustuous affair that saw Bolton book their ticket for a Wembley semi-final and ended Birmingham's hopes of adding more silverware to the Carling Cup, which they won last month.
Bolton led twice through Johan Elmander and a Kevin Davies penalty, only to be pegged back by Cameron Jerome and a sublime volley from 37-year-old Kevin Phillips. But there was no time for a third reply after Lee's late header.
In a highly watchable - if not conventionally beautiful - encounter, both sides favoured a direct, physical approach.
Although that did not make for pretty passing, it lent the game the pleasingly old-fashioned air of two good, honest teams banging heads.
Birmingham's teamsheet bore a distinctly patched-up look with manager Alex McLeish enduring the worst injury crisis of his tenure.
Just four players remained from the 11 who started the Carling Cup final at Wembley, and two of those were forced off within half an hour.
Bolton went in front on 21 minutes when Birmingham failed to clear a long Jussi Jaaskelainen clearance and Ivan Klasnic flicked deftly through to Elmander, whose low shot arrowed emphatically into the bottom-left corner.
Seven minutes before the break it was one apiece. A poor David Wheater clearance fell to the feet of Jerome, who had been previously poor. However, he controlled and lashed a high-speed daisy-cutter inside Jaaskelainen's near post from the left side of the box.
It might have been worse for Bolton when Jerome raced clean through and, at first glance, appeared to have been brought down by Jaaskelainen.
But the replay showed Phil Dowd's decision to award a corner to be an excellent one; the keeper getting a vital touch on the ball before colliding with Jerome.
Lee came off the bench with an hour gone, and almost immediately was forced into vital action, clearing a goalbound header off the line from a corner.
Shortly afterwards, Kevin Davies had a goal rightly chalked off after he strayed beyond the last man.
He did not have to wait long to dust off his celebration again, however. Curtis Davies clambered clumsily all over him inside the box and referee Dowd pointed to the spot. The Bolton skipper took the penalty himself and tucked it down the middle as Ben Foster dived out of the way.
The veteran Phillips was just denied by Jaaskelainen on 70 minutes, when the Finn touched his shot onto the post after excellent work by the striker.
But there was no denying Phillips with 10 minutes to go, when he contorted his body to hit a brilliant dipping volley over the keeper from 25 yards - worth every bit of the cramp his ageing legs suffered as a consequence.
Bolton were to have the final say, however. With the match drifting towards a replay, Paul Robinson launched a high ball towards Kevin Davies, who sent a cushioned header into the path of Lee, who beat Foster from six yards.