CHICAGO — As the Cincinnati Reds wind down another losing season, manager Bryan Price is hoping today’s pain is tomorrow’s gain.

“The thing is about September in our situation is, we’re looking at some of the younger players we brought up and sometimes there are painful lessons,” Price said. “It’s hard to go through, but the only way these guys are going to learn how to pitch up here is to pitch.”

The latest tough lesson came Tuesday night.

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 Cincinnati.

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.

“It’s fine,” Lester said. “It’s my right hand. I don’t need it. All it’s there for is to hold the glove.”

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.

The Cubs, who wrapped up the NL Central last week, are trying to find the right balance of staying sharp while getting rest and avoiding injury before the postseason. That’s why the crowd gasped and the trainer and manager Joe Maddon quickly ran out of the dugout after Lester was struck by Votto’s hard-hit ball.

After David Ross singled with two outs in the second, Lester lined a fastball off Josh Smith (3-2) into right-center. The 39-year-old Ross, who plans to retire at the end of the season, lumbered around from first and belly-flopped into home without a throw to put the Cubs ahead to stay.

“That’s more of a collapse than a slide,” Ross said. “I figured if I went headfirst it would be considered a slide.”

Smith, making a spot start in a bullpen game for the Reds, left after allowing three hits over three innings.

“He did fine,” Price said. “Really, the only mistake was the first-pitch fastball to Lester. We know there’s a pitcher hitting and the Cubs’ pitchers will be aggressive on a first-pitch fastball.”

Said Smith: “To get the chance to go against him and go against that team is a huge opportunity for me. I just went out there and tried to make the best of it.”

The Cubs scored four two-out runs in the fourth off Wandy Peralta, who walked Lester before Dexter Fowler’s RBI single. Kris Bryant followed with a bloop RBI double.

“We were hoping Wandy would give us a bit more than he did,” Price said.

With Washington losing 1-0 at Miami, the Cubs opened an eight-game lead over the Nationals with 11 left.

CY YOUNG WORTHY?

Lester lowered his ERA to 2.36 and improved his chances of winning the NL Cy Young Award. He twice finished fourth (2010 and 2014) for the AL prize.

“It’s a huge, huge honor to even be in consideration,” he said.

TRAINER’S ROOM

Reds RHP Homer Bailey (biceps) felt well enough that his bullpen session was moved up a day. Price was pleased and said it’s possible Bailey will get a start or two before the season ends. “There hasn’t been any issue regarding his surgically repaired elbow,” Price said.

UP NEXT

Cubs RHP John Lackey (9-8, 3.42 ERA), contending with Jason Hammel for the final postseason rotation spot, starts the series finale Wednesday night against RHP Robert Stephenson (2-1, 4.97).