The sweetest of derby wins may yet prove a mere appetiser. This was a triumphant afternoon for Norwich, who extended their hex over Ipswich to 15 years and fully deserved their extensive celebrations. They maintained a grip on the final playoff spot with an eighth straight home win and, in doing so, put a dent in their bitter rivals’ chances of automatic promotion. Ipswich had been top and flying before kick-off but were off the pace throughout and must hope the consequences of an uncharacteristically flat display are minimal.

While Leicester took advantage, Leeds’s defeat at Coventry kept Ipswich in the top two. Nonetheless these sides could do it all again next month, with a Wembley final at stake. That will be the case if Norwich retain sixth spot and Ipswich slip to third and, on this showing, David Wagner would fancy their chances of inflicting an even more grievous blow. His players were sharper, quicker and more aggressive in a scrappy game that was decided six minutes before half-time by a rare moment of quality from the dead-ball specialist Marcelino Núñez.

It was the Chilean who, during a spell of Norwich pressure that yielded a number of set pieces around the box, sized up his chance to strike gold from almost 30 yards. “I had a good feeling when he took the ball,” Wagner said, and it was borne out by a low, wickedly swerving strike that entered the net via a combination of Vaclav Hladky and his left post. Perhaps the Ipswich keeper could have done better; the mishmash of a wall in front of him certainly could and this time the division’s comeback kings had given themselves too much to do.

“At the end of the day my players were better,” said Wagner, who has come under ferocious criticism this season but finds himself in with a fighting chance of making his doubters look ridiculous. “I had the feeling they wanted it more, especially in the 50-50 challenges.”

Norwich certainly set out with a clear desire to disrupt Ipswich’s rhythm, thundering into tackles during an open early spell. But the match had begun to meander when, on the half-hour, Josh Sargent went beyond the Ipswich defence and was sent tumbling in a challenge with a recovering Axel Tuanzebe on the edge of the area. Replays showed Tuanzebe had won the ball but, once he had blown for a foul, the referee Matthew Donohue was tasked with deciding whether to dismiss the right-back. He settled for a booking; the incident riled an already boisterous home crowd and Norwich embarked upon the sustained attacking spell that would bring their winner.

“That decision, which I thought was incorrect, really lit the atmosphere,” said Kieran McKenna. “I did think that had an impact on the game.” But the Ipswich manager knew his side, generally thrilling to watch, had been well below their ferocious best. “I don’t think we managed to find our intensity. We didn’t hit the level we would have hoped in a game that I didn’t think was very high-level.”

Ipswich’s feted attack never got going, with Kieffer Moore unable to influence the game after being passed fit to lead the line and Omari Hutchinson, their exciting loanee from Chelsea, restricted to blind alleys. They could nonetheless have equalised when Conor Chaplin shot over from Leif Davis’s second-half cutback when favourably placed; the real one that got away came near the end when Ali al-Hamadi escaped the clutches of Norwich’s back line but saw Angus Gunn stand firm. Al-Hamadi was one of five second-half substitutes deployed by McKenna, a master at changing games from the bench, but this time they could not shift the dial.

In truth Norwich, content to sit in after the break but always a counterattacking threat, could have scored more. Sargent and the lively Borja Sainz both missed chances while Ipswich were also fortunate that their captain Sam Morsy escaped any form of punishment for seemingly fouling the American as he rampaged away again.

McKenna reached for some consolation. “The clubs will hopefully meet more regularly again and I’m sure this club will have its day as well,” he said. Wagner was promptly asked whether, should the next of those encounters take place next month, Norwich would hold a psychological advantage. “Yes,” he replied. Ipswich still retain hope that theory will not need testing.