Designated hitter Carney Lansford drove in four runs with three singles and a double and Gary Allenson and Dwight Evans homered to lead an 18-hit offense in Boston.
"I'm lucky to be playing at all," said Lansford, the league's defending batting champion, who is unable to play third base because of a bad ankle.
"When I first hurt the ankle I thought I'd be out for the season. Now, all of a sudden, it isn't that bad and I'm back in the lineup and able to make a solid contribution."
Lansford, who raised his average 10 points to .293, severely sprained his left ankle June 23 and went on the disabled list two days later.
He played six games at third after returning to action July 23, but his incomplete recovery forced him into the designated hitter's role July 29.
Jim Rice had a single, a two-run double and a triple and Wade Boggs had an RBI double and two singles as Boston ended its losing streak and Chicago's winning streak at three games each.
Tom Burgmeier (5-0) gave up one run in four innings after relieving Chuck Rainey in the fourth.
The Red Sox learned that the 5-year-old spectator whose skull was fractured by a foul ball Saturday was listed in good condition yesterday at Children's Hospital Medical Center. The boy, Jonathan Keane of Greenland, N.H., was undergoing more tests.