Teenager Josh Carson scored his first professional goals for Ipswich in a win that pushed Crystal Palace closer to the Championship relegation zone.
Carson, 17, opened the scoring on 38 minutes with a powerful shot in the area that beat keeper Julian Speroni.
He made it 2-0 after 66 minutes, latching on to Gareth McAuley's blocked shot from three yards out.
Paddy McCarthy then pulled a goal back for Palace with a volley from a Dean Moxey free-kick but Ipswich held on.
Palace are now five points above the drop zone, with Paul Jewell's Ipswich sitting mid-table in the league.
Afterwards, Jewell described the win as a "great day" for Carson and said he had a bright future ahead of him.
He said: "He's not fazed by playing in the first team and he was a thorn in their side, certainly for the first hour.
"He had lots of the ball and showed a few flicks and tricks - he certainly doesn't lack confidence and he's tough. He's not scared and he's got an eye for goal."
Ipswich's other teenage star Connor Wickham, who signed a new contract at Portman Road this week, got the home side off to a good start with a low shot that was just wide of the far post.
Speroni was then called into action as he parried a powerful Grant Leadbitter strike from 30 yards out.
But it was the visitors who enjoyed the next clear chance when Darren Ambrose seized on a loose ball inside the area but could not keep his effort down.
Palace were stirred into life and midfielder Neil Danns smashed a volley just wide before Ambrose stung the palms of Adam Lee-Barratt with a dipping strike.
The tables turned moments later when Carson went on a storming run down the right before cutting into the area and firing past Speroni at his near post.
Carson continued to shine in the second half when his cut-back found Carlos Edwards on the edge of the box but his left-foot effort struck the upright.
Wickham then volleyed wide, but Palace mounted a rare break and James Vaughan tested Lee-Barratt with a shot on the turn.
Ambrose then flashed a header wide and saw another shot saved before Carson grabbed his second and McCarthy pulled a goal back in the 73rd minute.