Jason Thompson hit a two-run homer and Manny Sarmiento held Montreal to one run in eight innings last night as the Pirates ran their winning streak to six games with a 4-2 victory over the slumping Montreal Expos in Pittsburgh.

It was the fourth loss in a row for the Expos and their ninth in their last 11 games.

After rain delayed the start of the game for 1 hour 37 minutes, Gary Carter gave Montreal a 1-0 lead in the second inning with his 17th homer this season. That was the only run off Sarmiento (3-1) until the ninth. He allowed five hits in eight innings but gave way to Kent Tekulve after Mike Gates and Tim Wallach singled to start the ninth.

The runners advanced as Al Oliver grounded out and Gates scored on Carter's sacrifice fly. Tekulve then retired Warren Cromartie on a grounder to earn his 10th save.

The Pirates moved ahead, 2-1, with two runs in the third off loser David Palmer (3-2). Dale Berra doubled, was sacrificed to third by Sarmiento's single. Moreno stole second--his 37th theft this season--took third on Johnny Ray's grounder and scored on Bill Madlock's single.

Thompson's two-run homer to center, his 16th of the season, followed a triple by Ray in the sixth.