Ipswich Town denied 10-man Leeds United the chance to move back into the Championship play-off places, thanks to Bersant Celina's long-range strike.
Celina curled the ball over Felix Wiedwald from 30 yards after Kalvin Phillips lost his footing.
Leeds midfielder Eunan O'Kane was shown a straight red card for an off-the-ball incident involving Jonas Knudsen.
Celina nearly added a second as his shot from outside the box beat Wiedwald but bounced back off the far post.
O'Kane's dismissal on 37 minutes changed the balance of a game that Leeds had largely controlled, although their finishing had let them down.
Leeds were without Samuel Saiz, who began his six-game ban for spitting at Newport County's Robbie Willmott during last week's 2-1 FA Cup third round defeat, while their cause wasn't helped by an injury to Pawel Cibicki before the half-hour mark.
But Thomas Christiansen's men had enough chances to level in a frantic game.
Kemar Roofe latched onto Pablo Hernandez's through-ball and cut inside Jonas Knudsen, but Luke Chambers blocked the striker's effort, while Pierre-Michel Lasogga had an effort saved by Dean Gerken.
Ipswich manager Mick McCarthy said:
"We needed the result over and above anything because we've had three defeats on the bounce and we needed to get our fans back on side here.
"I think their fans have helped more than anything else because they were brilliant and they created an atmosphere that was brilliant to play in and to manage in.
"They're a good side but we've had to scrap it out and we've played well, I'm really pleased."
Leeds United head coach Thomas Christiansen told BBC Radio Leeds:
"It was very difficult for Ipswich to defend us in the second half. We dominated and we had our opportunities to take a good result.
"In this situation it was a provocation. [Eunan O'Kane] didn't make a movement to hit. When two players hit each other and one dives as he [Jonas Knudsen] did, the one who stays on his feet is the one who receives the red card.
"Perhaps we have to train players to go to ground in this situation. I don't want that, but it's just frustrating when you see a game controlled and you don't take it.
"I think we should appeal because he didn't do anything. It was a provocation and they touched each other, and the only one who went to the ground was the opponent."