Luton striker Cauley Woodrow came off the bench to score a last-minute winner and heap even more pressure on Norwich boss Dean Smith as Hatters manager Rob Edwards recorded his first victory since taking over at Kenilworth Road.
It looked like Town were going to need to cling on for a point after being reduced to 10 men for the final 10 minutes when Gabriel Osho was sent off, only for Woodrow, who had just come on, to pick out the top corner with his first goal for the club and seal a 2-1 win.
Teemu Pukki had earlier cancelled out Allan Campbell’s second-half opener.
Luton should have led on 11 minutes when James Bree’s corner was met by Dan Potts and his powerful header glanced wide by Elijah Adebayo from close range.
Moments later, City forward Pukki went for goal from range, with Ethan Horvath able to watch it fly over.
With 20 minutes gone, Luton were inches away from breaking the deadlock, with Bree’s wonderful free-kick producing a brilliant save from Angus Gunn who tipped onto the bar and recovered to bat the ball away from Carlton Morris.
Gabriel Sara took matters into his own hands from 30 yards, his swerving drive parried by Horvath.
After the break, Town were hit by yet another injury concern as Adebayo limped off to be replaced by ex-Norwich striker Cameron Jerome.
He had an indirect part to play in the opener in the 61st minute as causing a nuisance to the visiting back line allowed Campbell to pick the ball up and then drive into the bottom corner from 22 yards.
Kenny McLean, sent off against Luton in the Hatters’ 1-0 win at Carrow Road earlier in the season, almost drew his side level, a deflected attempt shovelled behind by Horvath.
It was 1-1 in the 69th minute, though, when a ball forward was missed by Potts, with an unmarked Pukki making no mistake, gleefully drilling into the net.
Dimitris Giannoulis headed off-target as City looked to move in front themselves, before Tom Lockyer should have put Town ahead again, unable to direct his stretching header on target and then putting another attempt behind.
Norwich brought on Onel Hernandez and Isaac Hayden, the latter side-footing into the stands with one of his first touches.
With 10 minutes to go, the hosts were reduced to 10 men when Osho was shown his second yellow for a trip on Pukki.
There was no debating that decision, but his first yellow – when he looked to have won the ball fairly just before the break – was a controversial call.
Hernandez blasted the free-kick wide and then skewed off-target after some trickery inside the area.
Woodrow came on to be Luton’s hero, and Alfie Doughty ensured the hosts kept the points with a brilliant goal-line clearance from Hernandez in stoppage time.