Joel Youngblood, in his second game with Montreal, hit three singles and drove in three runs, Tim Wallach hit a grand slam homer and Tim Raines had five hits yesterday as the Expos defeated the Phillies, 9-2, with the help of 18 hits in Philadelphia. Seventeen of the hits were singles.

Charlie Lea (8-6), in his first start since July 20, pitched five innings. Reliever Byrn Smith held the Phillies to one run the last four innings in earning his second save.

Youngblood, obtained Wednesday from the New York Mets, had an RBI single during a three-run third and singled in two runs in the sixth. "I like this ballpark," he said. Last year in Veterans Stadium, Youngblood batted .538, going seven for 13 with one home run and seven RBI.

A business person's-special crowd of 52,327 watched the Expos finish starter Marty Bystrom (3-4) in the third, as Montreal salvaged the final of the four-game series after losing the first three.

Raines, who stole two bases, started the third with a bunt hit, stole second and Youngblood singled him in for a 1-0 lead. Youngblood went to third on Andre Dawson's single, Dawson stole second and Gary Carter singled in both.

The Expos increased their lead to 5-1 in the sixth on a walk to pinch hitter Wallace Johnson, a single by Raines, who then stole second, and Youngblood's two-run single.

Montreal's last four runs came in the eighth off reliever Sparky Lyle on singles by Raines and Youngblood, a walk to Carter and Wallach's 15th homer, his first grand slam in the majors, to left-center. Wallach had hit two homers Wednesday night off Steve Carlton.