PHOENIX -- Dallas Keuchel became the AL's first 20-game winner and the Houston Astros backed him with the highest-scoring game in team history, moving closer to a playoff berth by routing the Arizona Diamondbacks 21-5 Friday night.
The Astros have won five of six and held their one-game edge over the Los Angeles Angels for the second AL wild-card spot. Minnesota fell two behind.
Houston trails West leader Texas by two games with two to play.
Keuchel (20-8) gave up two runs on six hits in six innings, becoming the Astros' first 20-game winner since Roy Oswalt went 20-12 in 2005.
The AL wild-card game is scheduled for Tuesday, and the Yankees have already clinched a spot. If Keuchel pitched, it would mark the first time the All-Star lefty has started on three days' rest.
Carlos Correa hit a solo homer, bases-loaded triple and singled, and scored four times. George Springer, Colby Rasmus and Luis Valbuena homered as Houston surpassed its previous high of 19 runs set twice, most recently against Pittsburgh in 1999.
Springer and Rasmus also scored four times each as the Astros got a season-high 19 hits.
Keuchel is the 10th Astros pitcher, and second Houston left-hander, to win 20. Lefty Mike Hampton was 22-4 in 1999.
Keuchel is the second 20-game winner in the majors. The Chicago Cubs' Jake Arrieta won his 22nd on Friday.
Ruby De La Rosa (14-9) lasted three innings.
Arizona committed a season-worst four errors that led to five unearned runs. The Diamondbacks set a club record for runs allowed, topping the 20 they gave up at Colorado in 2003.
Peter O'Brien, a top Arizona prospect and a September call-up, hit a 471-foot shot into the picnic area in left field off Keuchel for his first big league home run.
Errors by Arizona third baseman Aaron Hill and left fielder Yasmany Tomas cleared the way for five runs in the first two innings. The Astros built a 10-2 lead through six, then entered club-record territory with a seven-run seventh and four-run eighth.
Springer's head-first slide just beat right fielder Socrates Brito's' throw at the plate for a run in the first. Twenty more followed.
Houston improved to 15-3 in interleague games, 7-1 on the road.
In case of a play-in game for the wild-card berth, Houston would travel to Minnesota if it's the Twins; the Astros would be home if it's the Angels. Houston last made the postseason in 2005.
Astros: OF Carlos Gomez sat out with sore ribs.
Diamondbacks: OF Ender Inciarte was out of the lineup after hitting a ball off his shin Thursday night. OF David Peralta injured his right wrist diving for a ball Thursday night. An MRI was negative but he did not play.
Astros: RHP Collin McHugh (18-7), the second half of Houston's potent 1-2 pitching duo, tries to clinch the Astros at least a tie for the wild-card berth.
Diamondbacks: RHP Jeremy Hellickson (9-11) makes his final start of the season for Arizona.