Carl Yastrzemski's second run-scoring single of the game broke a 3-3 tie and Carney Lansford followed with a two-run double as the Boston Red Sox rallied for three runs in the seventh inning and defeated the Cleveland Indians yesterday in Fenway Park, 6-4.

The big inning off John Denny (3-7) brought Boston's seventh victory in eight games. Cleveland dropped its fifth in a row, despite Andre Thornton's American League-high 17th home run and Toby Harrah's 12th, among four hits by Harrah lifting his league-leading batting average to .394.

Dwight Evans and Jim Rice singled to set the stage for the tie-breaking hit. Rice reached third on Yastrzemski's single but pulled his right hamstring on the way and was replaced by Reid Nichols. Lansford drove the ball off the left field wall, scoring Nichols and Yastrzemski.

Bob Stanley, with 4 2/3 innings of three-hit relief, was the winner, raising his record to 5-1.

The Indians wasted numerous opportunities, leaving the bases loaded in the first and eighth innings, two men on in the ninth, and causing Manager Dave Garcia to groan, "What can you do when you leave 15 men on base?" Actually, it was 14.