CHICAGO — Jake Arrieta pitched seven dominant innings and also homered in his major league-best 21st win, and the Chicago Cubs stopped Pittsburgh’s eight-game winning streak with a 4-0 victory Sunday night.

Arrieta (21-6) retired his first 18 batters before Gregory Polanco grounded a leadoff single into left field in the seventh. The right-hander homered in the second and struck out nine while improving to 15-1 with a dazzling 0.89 ERA in his last 19 starts.

Pittsburgh (95-61) and Chicago (90-65) each have clinched playoff spots and lead the NL wild-card standings, so the Pirates could see Arrieta again in the first game of the postseason on Oct. 7.

PHILLIES 12, NATIONALS 5: NL MVP front-runner Bryce Harper and Nationals closer Jonathan Papelbon got into a dugout fight a day after Washington was eliminated from playoff contention, tangling in the eighth inning of a loss to last-place Philadelphia in Washington.

BREWERS 8, CARDINALS 4: Jason Rogers hit a pinch-hit grand slam in the ninth inning off St. Louis closer Trevor Rosenthal to lift the Milwaukee to a win in St. Louis.

MARLINS 9, BRAVES 5: Justin Bour homered twice and drove in three runs, leading host Miami over Atlanta for a three-game sweep.

METS 8, REDS 1: Jacob deGrom pitched six sharp innings and New York, playing a makeshift lineup a day after clinching the NL East title, finished off a season sweep of the Reds with a victory in Cincinnati.

DIAMONDBACKS 4, PADRES 2: Ender Inciarte had two home runs among his four hits, leading Arizona over host San Diego.

ROCKIES 12, DODGERS 5: Nolan Arenado had a career-high five RBI, including a three-run homer, and Colorado swept Los Angeles, keeping the visiting Dodgers from moving closer to a third straight NL West title.

AMERICAN LEAGUE

BLUE JAYS 5, RAYS 4: Josh Donaldson hit a solo home run with two outs in the bottom of the ninth inning, connecting for No. 41 this year and sending playoff-bound Toronto over Tampa Bay at home.

YANKEES 6, WHITE SOX 1: Luis Severino pitched five-hit ball for six innings, Dustin Ackley homered to lift New York’s late-waking offense, and the Yankees moved closer to a playoff berth with a victory over Chicago in New York.

ANGELS 3, MARINERS 2: Kole Calhoun drove in the tiebreaking run in the eighth inning, and surging Los Angeles completed a sweep of Seattle in Anaheim, California.

ROYALS 3, INDIANS 0: Francisco Lindor broke up Kansas City’s no-hit bid with a bunt single off reliever Ryan Madson leading off the seventh inning, and the AL Central champions beat Cleveland at home as five pitchers combined on a two-hitter.

TWINS 7, TIGERS 1: Byron Buxton doubled in Minnesota’s six-run second inning, then hit his first career homer in the eighth in a victory in Detroit.

ASTROS 4, RANGERS 2: Dallas Keuchel improved to 15-0 at home, pitching Houston past Texas and cutting the Rangers’ lead in the AL West to 2 1/2 games.

INTERLEAGUE

GIANTS 5, ATHLETICS 4: Chris Heston won his first game in two months and San Francisco kept its slim NL West title hopes alive, building a five-run lead and holding on to beat host Oakland.