Rookie Matt Shaw blooped a walk-off single to right field in the 11th inning Tuesday night to propel the Chicago Cubs to a 4-3 victory over the visiting Colorado Rockies.

After Brenton Doyle’s RBI groundout gave the Rockies a 3-2 lead in the top of the 11th, Michael Busch tied the game with an RBI single off Tyler Kinley (0-2), who then walked Nico Hoerner and surrendered Shaw’s game-winning single.

Chris Flexen (3-0) pitched the 10th and 11th innings for the Cubs, allowing an unearned run on one hit. Cade Horton started for Chicago, surrendering two runs on four hits and one walk across six innings, striking out six. Ian Happ and Kyle Tucker each tallied a pair of hits for the Cubs, who have won six of their last seven games.

German Marquez allowed two earned runs on seven hits and a walk in six innings for the Rockies, striking out six. Doyle homered and drove in two for Colorado, which has lost nine of its last 10 games.

After Horton retired the first nine Colorado batters he faced, the Cubs struck first in the third. Shaw led off with a single and stole second before Happ singled and Tucker walked to load the bases. Seiya Suzuki drove in the game’s first run with a single to left and Pete Crow-Armstrong doubled Chicago’s lead with an RBI groundout.

Colorado cut its deficit in half in the fourth as Ryan McMahon’s two-out single scored Jordan Beck, who had been hit by a pitch and stole second.

The Rockies evened the score in the seventh on Doyle’s fifth home run of the season. Caleb Thielbar then relieved Horton, who struck out Tyler Freeman and retired Michael Toglia before allowing Kyle Farmer’s single and Adael Amador’s walk. Ryan Brasier relieved Thielbar and retired Beck to end the inning.

Jake Bird entered for Marquez in the bottom of the seventh, working a scoreless inning.

Freeman worked a one-out single against Ryan Pressly in the ninth but was caught stealing by catcher Reese McGuire. Toglia then walked, but Pressly induced Farmer’s inning-ending groundout.