Birmingham withstood a brave second-half fightback from Norwich to come away from Carrow Road with a 2-1 win.
The Blues scored twice early on to take a vice-like grip on an entertaining Championship encounter but were hanging on at the end as the in-form Canaries made a real game of it.
Carlos Vincente and Marvin Ducksch got the goals that put the hosts on the back foot but Norwich regrouped and Kenny McLean's well-taken goal midway through the second period gave them hope.
But the Blues held on to make it eight league games without defeat and add further momentum to a late push for the play-offs.
Birmingham came close to opening the scoring after just 24 seconds when it needed a good stop from Vladan Kovacevic to thwart Vicente after he had been put in by August Priske's flick-on.
But the Blues didn't have to wait long for the breakthrough, with the lively Vicente opening the scoring after five minutes. The Spaniard timed his run perfectly to latch on to Bright Osayi-Samuel's ball down the right flank and burst into the area before calmly sliding the ball pass the exposed Norwich keeper.
Birmingham made it two on 14 minutes with another goal set up by an astute pass from Osayi-Samuel. This time Priske was the recipient and with all the time in the world he squared for an unmarked Ducksch to side-foot home.
An in-form Norwich side struggled to produce a response and it was not until the 36th minute that they got a clear sight of goal, with James Beadle producing a smart reaction stop to keep out an acrobatic close-range effort from Mo Toure.
Beadle produced a brilliant double stop to thwart Toure and Kellen Fisher as the Canaries made a bright start to the second period, with Toure then striking an upright after racing through.
Norwich finally got the goal they had been threatening in the 67th minute. Ben Chrisene's cross from the left was only half cleared and fell nicely for skipper McLean to thunder the loose ball into the roof of the net.
Birmingham were firmly on the back foot but defended stoutly to see out the game.
Norwich's Philippe Clement:
"We had 62 per cent possession overall and more than double their attempts on goal and with those statistics you should be winning games.
"But early in the game we got caught by balls behind us too often. I thought the first 20 minutes was probably the worst we have been since I have been here and in the second half it was probably the best. All we were missing were the goals.
"Referees are human. They can't see everything and it's a shame they don't get the help this league deserves from VAR.
"I think the Championship is one of the top eight leagues in Europe but it doesn't have VAR so sometimes you have conclusions like this. It would also help young referees prepare for officiating in the Premier League if we had VAR."
Birmingham's Chris Davies:
"I thought that was one of our best away performances of the season. We have shown a bit of everything and the boys were very happy in the dressing room afterwards because they knew they had to fight all the way to get a win I thought we deserved.
"In the early stages I thought we were brave and aggressive on the ball, didn't let Norwich settle and were clinical in front of goal.
"In the second half we had to show the other side of the game - grit and determination - to come away with the three points. We were up against a Norwich side who have been flying recently and it's a really big win for us.
"What happens between now and the end of season I don't know but I am sure we will finish strongly and we'll just have to see where it takes us.
"I don't spend too much time looking at the table but I do know you could throw a blanket over a lot of teams and all we can do, and I know it's a cliche, is to take one game at a time."
