CHICAGO (AP) -- Jon Lester overcame an injury scare to throw seven strong innings, Anthony Rizzo drove in three runs and the Chicago Cubs moved closer to securing the NL's best record with a 6-1 victory over the Cincinnati Reds on Tuesday night.Lester (18-4) extended his scoreless streak to 21 innings before Jose Peraza's RBI triple in the fifth. He allowed six hits, struck out five, walked none and added an RBI double. Lester stayed in after Joey Votto's comebacker in the sixth left him with a welt on the wrist of his glove hand.Rizzo had a two-run single in a four-run fourth and a run-scoring single in the sixth to give him 104 RBIs. The Cubs' 96th win reduced their magic number to three over Washington for clinching home-field advantage throughout the NL playoffs.