Chelsea loanee Omari Hutchinson’s first goal for Ipswich was enough to earn them a 1-0 win at Southampton.
The Tractor Boys are up to second in the Sky Bet Championship after winning four successive away games in the second tier for the first time in eight years.
Saints, expected by many to go straight back up after last season’s Premier League relegation, have now lost their last three games.
Southampton started brightly and half of the St Mary’s crowd thought Adam Armstrong had scored with just five minutes played when he rippled the side-netting from the edge of the box.
Ipswich did have the ball in the net two minutes later, only for Conor Chaplin’s close-range effort from Hutchinson’s inswinging corner to be harshly ruled out for a foul.
Shea Charles passed up a presentable opportunity to test Ipswich goalkeeper Vaclav Hladky when he headed over from a Kyle Walker-Peters cross.
Brandon Williams then ballooned a header into the stands after rising at the far post to meet Wes Burns’ centre.
Ipswich took the lead on the half-hour mark after capitalising on a Charles mistake.
The Northern Ireland international was caught dwelling on the ball by Hutchinson just outside his own penalty area and the Chelsea loanee played a one-two with Chaplin before slotting home.
It was deja-vu for Saints six minutes later when Chaplin dispossessed Joe Aribo deep inside his own half before lofting his shot over goalkeeper Gavin Bazunu and onto the top of the crossbar.
The rebound fell kindly for George Hirst but the Ipswich striker could not keep his effort down.
Saints were booed off by their own fans at half-time but manager Russell Martin resisted the temptation to make any substitutions for the start of the second half.
Che Adams could have equalised four minutes after the restart but his effort from a Walker-Peters through ball 10 yards out was kept out by Hladky at full stretch.
Bazunu did well to throw himself low to his right and turn Chaplin’s well-struck left-foot volley from 20 yards away from goal.
Martin did turn to his bench in the 58th minute, bringing on experienced Premier League duo Jan Bednarek and Stuart Armstrong and winger Kamaldeen Sulemana.
Shortly after his arrival, Sulemana’s teasing low cross caused chaos in the Ipswich penalty area before Adam Armstrong’s shot was eventually smuggled behind for a corner.
Will Smallbone and Adams also had shots blocked as the Ipswich defence put their bodies on the line to preserve the victory.