Pablo Counago and Dean Marney tussle at Portman Road
Ipswich battled hard for a narrow win over third-placed Hull but missed out on the play-offs as Wolves and Crystal Palace won, and Watford grabbed a draw.
Hull, who were poor throughout, were also frustrated having gone into the game knowing a win coupled with a Stoke defeat would lead to promotion.
Ipswich had a goal controversially disallowed after three minutes and spurned a string of excellent chances.
Substitute Alan Lee grabbed the winner after an assist from Jonathan Walters.
The visitors, who began the game with a realistic chance of automatic promotion, forced just one save from Stephen Bywater, who stopped Nicky Barmby's header from close range.
Hull must now play Watford in the play-off semi-finals, while Ipswich's next season will again be played in the Championship.
The home team, with club president Sir Bobby Robson an interested spectator, began in exactly the way manager Jim Magilton would have wanted them to do.
Dominating the early exchanges, they forced Hull's defenders into a series of cynical tackles which resulted in three yellow cards for the team in yellow in the first 30 minutes.
With so much possession, Ipswich also carved out some excellent opportunities.
Notably, with the match barely under way, Pablo Counago's strike from the edge of the area hit the post and rebounded into the path of Shefki Kuqi.
The Finnish striker's header found the back of the net, but the goal was disallowed although there was no evidence of off-side or anything approaching a foul.
Irritated but undeterred, Ipswich continued to surge forward, with some of the passing in the final third of the pitch worthy of the Premier League.
Tommy Miller hit the outside of the upright on 19 minutes, after referee Andre Marriner intelligently waved play on following a dreadful Wayne Brown foul.
After the Ipswich midfielder had missed the chance, Marriner handed Brown an inevitable booking.
Soon afterwards, brilliant work from Counago inside the area saw play swept out to the left, but Alan Quinn scuffed his shot wide.
Quinn produced a much better effort from further out later on, but just cleared the crossbar, and three minutes before the interval Kuqi should have forced a save from Boaz Myhill, but hit a weak shot wide.
Hull started better in the second half, but Ipswich's passion saw them surging forward again as they continued to make advances on Myhill's goal.
Counago missed from 10 yards after a great run and pass from Owen Garvan, Quinn squandered two further chances and only Andy Dawson's excellent tackle on Counago prevented another golden opportunity.
But in the 69th minute, Lee scored moments after replacing Quinn.
His initial touch, a header to Walters on the left, was played back to the substitute who nodded into the bottom corner of the goal.
Ipswich comfortably held out for the remaining 20 minutes, but the victory could not mask their disappointment at missing out on the play-offs.
Hull manager Phil Brown: "Watford are not the form team of the moment so we'll probably be favourites.
"It's a lottery now. We're in the semi-finals of a cup. But over the 46 games, the players have been superb.
"We're disappointed we are just in the play-offs. Today was a bridge too far." More Hull quotes
Ipswich manager Jim Magilton: "We're going to be bringing in better players.
"We're going to get rid of the players who are not going to take us forward.
"It's a building process and we're getting there. No one said it was going to happen overnight."
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