The win put the White Sox 5.5 games out of the first place Minnesota Twins, who lost their fifth in a row.
Loaiza, who only pitched five innings in his last start because of a stiff neck and shoulder, went eight innings, giving up one run and striking out six. He is now 10-2 on the season with a 2.15 ERA; both are tops in the league.
The Red Sox went up 1-0 in the fourth inning with a fielder's choice groundout by Nomar Garciaparra. Scoring was Johnny Damon, who singled and advanced to third on a single by Todd Walker.
The White Sox walked twice in the first four innings, but didn't get their first hit until the fifth, when Joe Crede singled. After a passed ball moved him to second, Jose Valentin walked to bring up Miguel Olivo with one out. Olivo then doubled to score Crede, the tying run, but Valentin was thrown out at the plate. Replay's showed Boston catcher Doug Mirabelli never applied the tag.
D'Angelo Jimenez had two key leadoff walks in the game, coming in the sixth and eighth innings, with both resulting in runs.
Jimenez stole second in the sixth, and after a walk by Magglio Ordonez, advanced to third on a fly out by Carlos Lee. Jimenez then scored the eventual winning-run on a Brian Daubach double.
Jimenez scored the final run on an Ordonez double in the eighth off reliever Rudy Seanez. A single by Frank Thomas moved to Jimenez to third.
Billy Koch came in and recorded his ninth save with a scoreless ninth inning. Koch put two men on in the inning.
Up 2-1 in the series, game four will be Thursday at 1:05 p.m. CT, with Danny Wright going up against Derek Lowe. The game will be televised on WGN.