The Texas Rangers have won seven straight over the second-place Houston Astros and can take a major step toward their first AL West title in four years this weekend.
They may have the right person on the mound to start this three-game series.
Yovani Gallardo has beaten the Astros more than any other club and will get the ball Friday night in Houston.
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Texas (83-69) has a magic number of seven to capture the West after sweeping three games in Oakland to start this six-game trip following Thursday's 8-1 victory. The Rangers have won nine of 11, including a four-game home sweep of the Astros from Sept. 14-17.
''They've got some great energy right now, superior focus and they're on a mission,'' manager Jeff Banister said. ''Each one of them knows where we want to go. We're not there yet so they maintain that focus.''
Texas trailed by eight games in the West race Aug. 2. Now Houston (80-73) may be better served by focusing on holding off Minnesota and Los Angeles for the second wild card.
The Astros are losers of seven of 10 after Wednesday's 6-5 defeat to the Angels.
''We're right in the thick of this,'' manager A.J. Hinch said. ''We're in the thick of the division; we're in the thick of the wild card with our sights set on a really big series against Texas.
''I downplay everything for five months, five-and-a-half months to get to this series. There's no downplaying it. I'm not going to sit in front of you and say it's not an important series.''
Gallardo (12-11, 3.41 ERA) is tied with Philadelphia's Aaron Harang for the most wins against the Astros among active pitchers, going 15-4 with a 3.09 ERA. He is 2-1 with a 6.14 ERA in three 2015 matchups.
"I know these next three games are going to be very important," Gallardo told MLB's official website. "For me, I have done it before, but you still have to make pitches no matter what the situation. It will be more exciting, that's for sure, than other games."
Houston has some lefty-swinging hitters who have fared well against the right-hander in Jason Castro (.350), Luis Valbuena (.321) and Colby Rasmus (.318).
Gallardo has failed to get out of the sixth inning in five consecutive starts, allowing three runs in five-plus innings in Friday's 3-1 home defeat to Seattle.
His mound opponent, Scott Kazmir (7-10, 2.73), turned in his shortest start with the Astros by allowing three runs in 3 2-3 innings in Saturday's 10-6 win over the Athletics. Kazmir is 0-2 with a 4.50 ERA in his last five starts.
The left-hander is 2-1 with a 1.60 ERA in five starts this year versus the Rangers. Prince Fielder, Shin-soo Choo, Delino DeShields and Adrian Beltre are a combined 5 for 39 against him in 2015.
DeShields is 7 for 14 with six RBIs in his last four games. Beltre was 6 for 14 with eight RBIs in the Oakland series.
"The main thing is not putting pressure on ourselves," DeShields said. "It's really ours to lose."
The Astros' Carlos Gomez has missed the last 11 games with an intercostal strain and is unlikely to play this weekend.