Birmingham City travelled to Carrow Road carrying the distinction of being the last unbeaten side in the Championship. They did not leave with it. A 2-1 defeat to Norwich ended what had been a promising unbeaten run, and the manner of it will sting particularly hard for supporters who felt the night might have turned out very differently.

A goal that wasn't, and a game that slipped away

The pivotal moment arrived early. Blues had pressed Norwich effectively and looked the sharper side when what appeared to be Liam Millar's opening goal was ruled offside. Fan writer Kym Smith, reflecting on the evening for BBC Sport, noted that replays suggested Millar was "more than likely onside." Whether the flag was correct or not, the psychological effect of having a perfectly good goal chalked off is rarely neutral, and Birmingham never quite recovered their rhythm.

Within minutes, Oscar Schwartau struck a screamer to put Norwich ahead. It was an excellent finish, but Birmingham's defensive shape deserves scrutiny: Schwartau was afforded far too much space to wind up his effort, and that generosity proved expensive. Before the half was out, Papa Diallo doubled the home side's advantage. Smith pointed to a lack of concentration from Tomoki Iwata and Christoph Klarer as the root cause, and it is difficult to argue with that assessment on the evidence of the goal.

Second half: glimpses, but not enough

Birmingham came out for the second period in what Smith described as "a rather discombobulated state," and both sides contributed to a scrappy opening to the half. The introductions of Alex Cochrane and Ethan Laird shifted the dynamic slightly, giving Blues more attacking momentum.

Vicente pulled one back, tapping home a good cross from Millar, and for a spell it genuinely felt as though a point might be salvaged. Goalkeeper James Beadle played his part, making a couple of important saves to keep Birmingham in contention. The clearest chance to equalise arrived when Beadle's excellent long ball found Jay Stansfield, and the move looked certain to result in a goal. Vicente, however, appeared to hesitate at the critical moment, unsure whether to cross or shoot, and the ball squirted away. It is the sort of chance that, on a better night, finishes in the net.

What does this defeat actually tell us?

Here is where it is worth being careful. One defeat after an unbeaten run does not unravel a season, and the evidence from the match suggests Birmingham were not outclassed. They pressed well in spells, created the better late chances, and only lost by a single goal despite conceding twice before the break. The disallowed goal aside, the scoreline might have looked very different.

That said, the defensive lapses at set pieces and in midfield are a recurring concern that this result does nothing to dismiss. Giving Schwartau that much room to shoot, and switching off for the second goal, are habits that will be punished repeatedly at this level if they are not addressed. Birmingham do not yet have the numbers to say whether these are isolated errors or a structural problem; a larger sample of matches will be needed before that can be settled with any confidence.

The immediate focus now turns to a lunchtime trip to Pride Park on Saturday. A quick response is possible; Birmingham have shown enough quality this season to suggest they can bounce back. Whether their luck turns is another matter, though luck, as a rule, tends to follow sides that eliminate the avoidable mistakes first.

Frequently asked

Why was Liam Millar's goal disallowed against Norwich?
Millar's goal was ruled out for offside, though replays suggested he was more than likely onside when the ball was played to him.
What was the score when Birmingham City played Norwich City at Carrow Road?
Norwich City won 2-1, with Oscar Schwartau and Papa Diallo scoring for the hosts and Vicente pulling one back for Birmingham in the second half.
When is Birmingham City's next Championship game after the Norwich defeat?
Birmingham's next fixture is a lunchtime kick-off away at Pride Park on Saturday.