The substitute, who had only been on the pitch for a matter of minutes, kept his cool to fire home an equaliser as Bruges were denied revenge for their first defeat on home soil by an English side two weeks ago.
Belgian blast: Thomas Meunier puts Club Brugge ahead
MATCH FACTS BIRMINGHAM CITY (4-4-2): Doyle, Spector, Caldwell, Ibanez, Murphy; Elliott (Burke 66mins), Fahey, N'Daw, Beausejour; Rooney (Wood 66), Zigic (King 66).
Subs not used: Myhill, Ridgewell, Redmond, Davies.
Booked: Zigic, N'Daw
Scorers: Beausejour 55, King 73 (pen).
FC BRUGES (4-3-3): Kujovic, Van Acker (Almeback 85), Donk, Van Gijseghem, Vansteenkiste; Odjidja, Zimling, Vazquez; Dirar, Akpala (Vleminckx 76), Meunier.
Subs not used: Coosemans, Rafaelov, Perdichizzi, Derschilder, De Johnge.
Booked: Akpala, Donk
Scorers: Meunier 39, Akpala 43
Referee: M Borski (Poland)
Man-of-the-match: Jean Beausejour.
King took full advantage after visiting skipper Ryan Donk had been penalised for a foul on Jean Beausejour.
The ex-West Brom defender was unfortunate that Polish referee Marcin Borski had ruled against him after what appeared to be little more than a tangle on the left-hand edge of the box.
But King was in no mood to allow anysentiment to get in the way and fired home from the spot after Birmingham had suffered a double blow inside four chaotic minutes late in the first-half.
A rare lapse at a corner allowed Thomas Meunier to volley home.
That had been followed by a breakaway goal that was finished with striker Joseph Akpala standing at least one yard offside.
It left Hughton's side, who have played on average every four days since the start of the season, facing adesperate scrap to ensure that their hopes of escaping Group H remainedalive.
Defeat here would have almost certainly meant Birmingham would need to win their final two matches to progress.
As it is, four points from those games will see them through to the knockout stages.
Tom terrific: Meunier (19) is conratulated after putting the visitors in front
'When you go two goals behind against a very good footballing side, you fear the worst,' said Hughton, 'but it'stestament to the spirit within the camp that we came back.
Late show: Marlon King levels from the spot
Bitter Brum: Total dejection after conceding a second goal
So close: Birmingham's Zigic (right) heads wide
'Bruges have a lot of quality in their front six but I knew that if we could get one goal back then therewas a chance we could get more.'
Bruges's stand-in coach Rudi Verkempinck confirmed that Steve McClaren was on the shortlist to take over from Adrie Koster, as revealed in Sportsmail yesterday.
Woodwork woe: David Murphy's free-kick hits the crossbar
He said: 'He is one of a number of people who I understand the club is looking at.'
Paying tribute to Birmingham, he said: 'They have a lot of power and when they started with that power-play it was difficult for us.
'We kept it at 2-2 for the final 15 minutes. The pressure kept on coming but I think overall it was the correct score.'
Flattened: Murphy battles with Club Brugge's Nabil Dirar
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