Ipswich gave their hopes of automatic promotion from the Championship a massive boost by recording a hard-fought 2-0 win over Norwich at Carrow Road.
Town moved into the top two, with two games in hand on third-placed Millwall, as first-half goals from Jaden Philogene, with a harsh penalty, and George Hirst completed a long overdue double over their East Anglian rivals.
Norwich had more of the ball but were frustrated by an impressive defensive display from the visitors, who kept the number of clear-cut chances down to a bare minimum.
The defeat ended any faint chance the Canaries had of making the play-offs - although the fact they are heading for a top-10 finish is still a remarkable achievement for a side who were in the bottom three at the start of the year.
Ipswich grabbed the lead in controversial fashion after just 11 minutes.
Anis Ben Slimane accidently caught Jack Taylor as he attempted to hook the ball clear in the area but referee Anthony Backhouse decided it was a penalty and Philogene sent Vladan Kovacevic the wrong way from the spot.
The Norwich 'keeper then did well to palm away Hirst's header from a deep free-kick but the hosts gradually began to work their way into a frenetic encounter, pinning their rivals back for long periods.
They had plenty of the ball but clear-cut chances were few and far between and Pelle Mattsson's powerful shot, which Christian Walton grabbed low to his right, was a rare moment of danger for the visitors.
It needed another good stop from Kovacevic, this time with his feet, to deny Hirst just before the break - but moments later Town doubled their lead.
Darnell Furlong's long throw from the left was flicked on and an unmarked Hirst volleyed home to give his side a flattering two-goal advantage.
Norwich made two attacking substitutions at the break, with Mo Toure and Oscar Schwartau coming on, and Slimane was quick to test Walton following a quick break.
Toure then scuffed a shot wide from a decent position before the arrival of ex-Canary Marcelino Nunez off the Ipswich bench upped the already frenetic atmosphere to even higher levels.
Town should have made it three following a swift counter-attack but Taylor was denied by another excellent Kovacevic save before Nunez, who had picked up a booking, was substituted for his own good after an edgy cameo.
Norwich's Philippe Clement:
"We started well but then we were hit by a penalty which was not a penalty. mAnis goes to clear the ball, their player dives into him and Anis doesn't touch his leg. We have a transition and then four or five seconds later the referee gives a penalty. That is why I support VAR - you have to get these decisions right.
"After that my players kept fighting, trying to play good football, but we didn't finish it off, we didn't create enough in the final third. That is something we will be working on in the coming weeks."
Ipswich's Kieran McKenna:
"This is a brilliant result for the club. As soon as I came here I was told how important this fixture was and that it had been so long since we'd beaten them.
"We finally got a win at our place earlier in the season and now we've backed it up by completing a double. I know how much this means to everyone connected with the club and I am sure they will all be enjoying it.
"We came here with a game plan and the lads have done a brilliant job in what was a really tough game and delivered something special for the fans.
"We had to concede territory at times but we defended really well, got our headers and tackles in, and showed great resilience and togetherness to get the job done.
"It's another important three points but there's another game coming up on Tuesday (at Portsmouth) so we won't have too long to enjoy it. Hopefully we can celebrate this properly in three weeks' time."
