PHOENIX -- The Houston Astros are finishing fast and will be playing somewhere next week. Just where and against whom is yet to be determined.
The Astros remained in contention for the AL West title as well as the league's first wild card.
"All these games the last week have felt like playoff games for us," McHugh said.
McHugh (19-7), pitching a night after teammate Dallas Keuchel won his 20th game, allowed a run and six hits in seven innings to improve to 6-0 in his last seven starts.
"He did what he always does," Arizona manager Chip Hale said. "He throws his cutter, curveball and spots his fast ball. He had us off balance and we didn't make much hard contact."
Jose Altuve homered and doubled for Houston.
Astros manager A.J. Hinch called it "a needed win, and certainly putting pressure on a lot of teams around us."
Paul Goldschmidt hit his 32nd home run for the Diamondbacks.
The Astros, who set a club scoring record in a 21-5 rout of the Diamondbacks on Friday night, have won six of seven to help scramble the AL playoff picture.
"The whole race, the whole season has been wild for us," Rasmus said.
The Los Angeles Angels' 11-10 comeback win at Texas left Houston a game behind the first-place Rangers. An Astros win on Sunday and a Rangers loss would send Houston into a one-game tiebreaker at Texas on Monday for the division crown. The loser would play the New York Yankees in the wild-card game.
If the Astros lose on Sunday and Los Angeles wins, the Angels would go to Houston on Monday for a tiebreaker to determine the second wild card. A Houston loss and a Texas victory would give the Astros the No. 2 wild card and a trip to Yankee Stadium.
And if Houston and Texas both win, the Astros could wind up the top wild card and host the Yankees if New York loses its regular-season finale at Baltimore. Houston holds the tiebreaker over the Yankees because it won the season series 4-3.
"Nothing can happen to us negatively if we win (on Sunday)," Hinch said. "We'll be playing for the division or be in the wild card."
McHugh said there's no sense thinking about the dizzying array of possibilities.
"If you start trying to figure out what can happen here, what can there and the ifs and the buts, it's going to get in your head," he said.
Rasmus led off the fourth and eighth with his 24th and 25th home runs, respectively.
"I was excited to come here," Rasmus said. "It's always been a fun place to hit and we've taken advantage of it."
Altuve was hit in the hand by David Hernandez's pitch with the bases loaded in the eighth inning. He shook his hand in pain but stayed in the game.
The Astros are a major league-best 15-3 in interleague play, 8-1 on the road.
The right fielder made a big play for each team.
Socrates Brito's perfect, one-bounce throw caught Houston's Chris Carter trying to advance to third on a flyout in the second. George Springer's driving grab down the right-field line for Houston robbed Aaron Hill in the third.
Astros: OF Carlos Gomez sat out his second consecutive game with sore ribs.
Astros: Hinch said after the game rookie RHP Lance McCullers (6-7, 3.21 ERA) will start on Sunday.
Diamondbacks: LHP Robbie Ray (5-12, 3.12), who has allowed two earned runs in his last two starts, takes the mound in Arizona's last game of the season.
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