Adam Morgan's sixth start in his comeback from left shoulder surgery was his best.
But he'll have to wait at least another five days before getting his first win since 2013.
Gwinnett used a passed ball, two wild pitches and a bloop single to fuel a four-run, eighth-inning rally en route to a 5-1 victory over Lehigh Valley in front of 10,100 at Coca-Cola Park.
The loss ended a three-game winning streak for the IronPigs (9-21), who walked five more to extend their league-high total this season to 133.
"We didn't capitalize on our opportunities and they took full advantage in the eighth inning of our mistakes," IronPigs manager Dave Brundage said.