Grissom rounded the bases without ever hesitating last night as third base coach Jerry Manuel gave him the green light.
"I only started getting tired around third base, but he kept waving, and I kept running," Grissom said.
Centerfielder Gerald Young didn't appear to read Grissom's leadoff hit well. He raced back to try an over-the-shoulder catch, but the ball hit the heel of his glove and took a strange hop on the artificial surface.
"I was surprised by how far it carried," Young said.
Young bobbled the ball momentarily before relaying to shortstop Ozzie Smith, whose throw to the plate was just late.
"Anytime a player like him hits a ball that far, you have to execute the play cleanly," Smith said. "Everything has to be clean or it'll cost you. And it cost us."
Grissom's 10th homer, and third in as many games, gave the NL East-leading Expos their 12th victory in their last 13 games.
John Wetteland (3-6) got the win after allowing St. Louis to tie the game with two outs in the ninth on Geronimo Pena's 11th homer.
In other news:
METS: CASTILLO SENT DOWN
The New York Mets optioned pitcher Juan Castillo to Triple A Norfolk and recalled righthander Doug Linton from Norfolk.
CARDINALS: TO ACTIVATE CORMIER
St. Louis Cardinals pitcher Rheal Cormier, disabled since May 21 with an upper back injury, will be activated and start tomorrow against the Expos. St. Louis will likely option rookie Gary Buckels to Triple A Louisville.