Jack Flaherty struck out nine in seven strong innings and catcher Matt Wieters hit a three-run homer as the Cardinals beat the Chicago Cubs 8-0 in a matchup of NL Central leaders.
The Cardinals won two games in the three-game set and claimed first in the division, a game ahead of Chicago. The Cubs have lost four of six overall and 11 of their last 16 on the road.
Flaherty (5-6) allowed just one hit and walked two in recording his first win since May 14, a span of 79 days and 12 starts.
Jose Martinez, Kolten Wong and Yairo Muniz had RBI singles for the Cardinals, who are coming off a 16-9 record in July.
Lester (9-7) gave up five earned runs on nine hits over five-plus innings. He struck out six and did not walk a batter.
Wong and Paul DeJong had three hits apiece.
Jose Quintana (8-7, 4.47 ERA) faces off against Milwaukee RHP Zach Davies (8-4, 3.56 ERA) on Friday afternoon as the Cubs open up a three-game series at Wrigley Field. Quintana is 6-4 with a 2.80 ERA in 14 lifetime starts against the Brewers.
Dakota Hudson (10-5, 3.88 ERA) squares off Saturday against Oakland's Mike Fiers (9-3, 3.54 ERA) in the first of a two-game set in Oakland following a rare Friday night off. Hudson allowed three home runs in his last outing - a 6-2 loss to Houston on Sunday.