MILWAUKEE -- The Brewers just keep surging in September.

A 5-1 win over the Padres on Thursday at Miller Park gave the Brewers 12 wins in their last 14 games and a fifth series victory since their last series loss, while keeping the heat on the Cardinals and Cubs in baseball’s tightest division.

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Craig Counsell’s club is an MLB-best 14-4 this month and 34-11 under expanded roster rules the past two years. Milwaukee has continued to win since losing Christian Yelich to a season-ending knee injury thanks to games like Thursday, when starter Jordan Lyles pitched well but was subject to an early hook, and four relievers finished a win in which three players drove in a run, including Lorenzo Cain on a fourth-inning solo homer before he exited with a sore left ankle.

The victory kept the Brewers three games behind the Cards in the National League Central standings and brought them within one game of the idle Nationals for the top NL Wild Card spot. The Brewers moved a game ahead of the Cubs for the second NL Wild Card spot, with St. Louis winning the opener of a critical four-game series against Chicago at Wrigley Field on Thursday night.

“From my perspective, we’ve been in playoff games since the last day of August,” Counsell said Thursday afternoon. “That’s how we’ve treated the games. We’ve had to.”

This is the last year in which active rosters expand on Sept. 1 from 25 to include anyone from the 40-man roster, and Milwaukee has made as much of the extra help as any team in the league over the past two years:

• Last season, the Brewers were 15th of 30 MLB teams with a 3.94 ERA from Opening Day through the end of August, but they were best in MLB with a 2.70 ERA from Sept. 1 through the end of the regular season.

• This year, the Brewers have made a similar jump. They were 18th with a 4.68 ERA through Aug. 31, and they’re second best in MLB with a 3.22 ERA since Counsell’s bullpen options expanded.

“It has a lot to do with the way that Craig manages his bullpen,” Lyles said. “Last year, it was a different set of guys. But when there’s trouble around that third time through the lineup, he’s leaning on his guys who have gotten him to this point. You can’t argue with the numbers -- third time through the lineup, it’s good to get a fresh arm in there.”

Take the fifth inning on Thursday. Lyles had allowed only one run on three hits, and he was two outs shy of qualifying for a seventh win in 10 Brewers starts when he started “spraying the ball all over the place” and walked the first two hitters of his third pass through the Padres’ lineup. Wil Myers followed with a popout behind home plate, but Counsell then opted for reliever Freddy Peralta to face Eric Hosmer, who’d homered off Lyles in the fourth.

Peralta, firing fastballs that topped 98 mph, struck out Hosmer to end the threat. An inning later, the Brewers essentially put the game away when Trent Grisham's Little League homer -- he hit an RBI double, took third on the throw home and scored when Padres catcher Austin Hedges’ throw to third base sailed into the outfield -- added two insurance runs.

“It allows you to be more aggressive,” Counsell said. “It allows you to give guys rest. And it’s allowed our guys to get into a lot of big situations, and they’ve had success, and I think they have confidence from that. Really, what it’s done for us is expanded the group of guys we’re leaning on. I think that’s worked for us. I think it’s helped our starters in that they go hard for a little bit shorter. Chase Anderson is a good example; his stuff has ticked up since we got to September. And that’s a great sign at the end of the season.”

Counsell added, “It’s just, ‘Go as hard as you can and let’s see what happens.’”

Why have the Brewers particularly thrived in the final month? It could have something to do with how president of baseball operations David Stearns has built pitching staffs. There are no Max Scherzers or Justin Verlanders in Milwaukee unless they’re visiting; rather, Stearns has focused on depth. That was evident at the July 31 Trade Deadline when instead of trading top prospects for a top starter, Stearns went for multiple arms in a series of deals to help cover injuries, which at the time included All-Star starter Brandon Woodruff and Opening Day starter Jhoulys Chacín, who has since been released.

Stearns got Lyles from the Pirates while Lyles was slumping. He got Drew Pomeranz and Ray Black from the Giants for infield prospect Mauricio Dubon, who is good but perhaps not as good as second baseman Keston Hiura, whom Stearns held. Pomeranz, who has thrived since moving to relief at the end of his stint with San Francisco, pitched the seventh inning Thursday. Black worked the eighth and the start of the ninth before Josh Hader cleaned up a mess for his 34th save, breaking Dan Plesac's franchise record for saves by a left-handed pitcher.

“I think David has done a really good job of -- and it’s always at the forefront of his conversations -- is depth,” Counsell said. “And I think that helps in these situations. It helps me probably be more comfortable being aggressive.”

While the Cardinals and Cubs tangle at Wrigley Field, the Brewers will try to stay aggressive against the Pirates. They are the opponent for Milwaukee’s final regular-season series at home beginning Friday.

“We understand what’s at stake, what we need to do to get to the playoffs,” Cain said. “We understand it’s not going to be easy.”