DENVER (AP) -- Nolan Arenado hit a grand slam, German Marquez pitched five solid innings for his first major league win and the Colorado Rockies slowed the St. Louis Cardinals' playoff chase with an 11-1 victory on Wednesday.The Cardinals entered the day tied with New York and San Francisco atop the NL wild-card standings. The Mets and Giants both played later.Arenado broke open the game in the second with his NL-leading 39th homer of the season. His fourth career slam made it 6-1. Luke Weaver (1-4) was roughed up by the Rockies, surrendering seven hits and six runs in two innings. Before this game, the right-hander had allowed 12 earned runs in his last seven starts combined.This was a memorable day for Marquez (1-0), who made his first big league start after three appearances out of the bullpen. He allowed one run and struck out three.At 21 years, 212 days, Marquez was the second-youngest pitcher in Rockies' history to earn his first win, the team announced. The youngest was Jamey Wright (21-206).The hard-throwing Marquez was acquired in January as part of the deal that sent outfielder Corey Dickerson to Tampa Bay. Marquez pitched a majority of the season for Double-A Hartford, where he was chosen as the pitcher of the year in the Eastern League.Marquez worked his way out of several dicey situations against the best road team in baseball. He allowed his only run in the second, when Jeremy Hazelbaker led off with a double and later scored on Kolten Wong's sacrifice fly.The Cardinals took two of three from Colorado during a series in which their starting pitchers were brilliant at the plate. Carlos Martinez, Adam Wainwright and Weaver went a combined 4 for 4 with two doubles and six RBIs. Weaver had a single in his only plate appearance.DJ LeMahieu got two hits and drove in two runs to raise his average to .351. He holds a slight lead over Washington's Daniel Murphy in the NL batting race.