Tommy Smith swooped to earn Ipswich their first Sky Bet Championship win of the season as new-look Sheffield Wednesday were beaten 2-1 at Portman Road.
The two sides shared a goal apiece inside two minutes of each other in the first half, with Ross Wallace firing Wednesday in front in the 19th minute before Freddie Sears took advantage of indecisive defending to equalise.
Smith grabbed what proved to be the winner eight minutes into the second half when Ryan Fraser's fierce cross was diverted on to the centre-back's head via a deflection off visiting keeper Keiren Westwood.
On the back of six goals and two wins in the opening few days of the Championship season, Wednesday began brightly and almost took the lead with just four minutes gone.
Jack Hunt's long ball caught Luke Chambers cold and Marco Matias found space to get a half-hit shot away which beat Bartosz Bialkowski but came back off the post.
At the other end, Daryl Murphy had a shot beaten away by the diving Westwood on 11 minutes before a last-ditch block from Hunt denied Fraser's shot at goal.
Against the run of play, the visitors took the lead on 19 minutes when Matias outpaced Smith and while Bialkowski did well to save low down, Wallace rifled the rebound into the roof of the net.
Just two minutes later, Ipswich were level. A hopeful long ball from Chambers dissected Jeremy Helan and Glenn Loovens to set Sears clear and he drilled a pacy shot inside Westwood's near post.
A frantic first quarter - and two razor-sharp goals - was followed by a tight last 20 minutes of the first half.
Ipswich almost took the lead quickly after the restart when Christophe Berra stooped to meet Fraser's corner but Lewis McGugan was on hand to clear off the line.
But the home side did go ahead after a frantic period of pressure which ended with Fraser getting to the byline and though his cross was diverted by Westwood, Smith was on hand to nod home.
Wednesday were forced to take off the injured Westwood and his replacement, Joe Wildsmith, was called into action immediately, diving to his left to deny the onrushing Sears.
Wednesday hit back and a quick counter saw Wallace test Bialkowski at his near post with 18 minutes left before a nervy finish saw Berra have a second header cleared off the line and Lucas Joao's fierce run and shot only thwarted by the diving Bialkowski.
Ipswich Town manager Mick McCarthy:
"Near the end I'm sure my heart was going a little faster than it should, but we were bound to be a little nervy. I think it was a good performance. We had to come from behind to beat a very good team, which means we showed all the attributes you need to be a success in this league."
Sheffield Wednesday manager Carlos Carvalhal:
"I am unhappy about the result but I am proud of my players, who fought for the whole 96 minutes, and also our fans, who supported the team during and after the match. We knew this would be one of the hardest matches in the Championship but in some parts we controlled the game and we put Ipswich under pressure in the last 15 minutes."