Starter Nathan Eovaldi held the Astros to five hits and two runs over 6 1/3 innings and the Rangers hit three home runs to win Game 6.
"We knew they weren't just going to roll over," Eovaldi told reporters, when asked about the Astros. "It's big for us to be able to turn the page and be able to lock in. We gotta do the same thing [Monday]. It's win or go home. We have to make sure we do what we did [Sunday]."
The Rangers totaled five hits and three runs over five innings in the loss. Designated hitter Mitch Garver went 3 for 4 with a home run, two RBIs and a run scored. Catcher Jonah Heim and right fielder Adolis Garcia also homered for the Rangers.
"I've said it from the middle of August that it was going to be a dogfight all the way to the end," Garver said. "Really, really good ball clubs on both sides. They have pitching. They have hitting. But so do we.
"It's one game to settle it all and I think everybody is pretty excited for that."
The Astros drew first blood in Game 6, with designated hitter Yordan Alvarez raking an RBI single to center field in the bottom of the first inning off Astros starter Framber Valdez. Garver then tied the score with a 375-foot solo homer in the top of the second.
Heim lifted a 336-foot two-run homer over the right field fence in the top of the fourth for a 3-1 edge and the Rangers never trailed again.
Center fielder Mauricio Dubon cut the deficit to one with an RBI sacrifice fly in the bottom of the sixth for the Astros' final run of the night.
Garver added to the Rangers lead with an RBI double in the eighth. The Rangers added five runs in the ninth to put the game away.
The Rangers loaded the bases to start the bottom of the inning. Astros relief pitcher Ryne Stanek then hit shortstop Corey Seager with a pitch, pushing the Rangers lead to three runs.
Two at-bats later, Garcia crushed a 1-1 fastball to left field for a 375-foot grand slam for the final runs of the night.
The Rangers bullpen allowed just one hit and no runs over the final 2 2/3 innings of the victory. Rangers second baseman Marcus Semien reached base four times, with two hits and two walks in five plate appearances.
The Astros will host the Rangers in Game 7 at 8:03 p.m. EDT Monday at Minute Maid Park. The game will air on FS1.
Scherzer owns a career 7-8 record and 3.80 ERA in the postseason. He surrendered five hits and five runs over four innings to the Astros in Game 3 of the ALCS on Wednesday in Arlington, Texas.
Javier is 6-1 with a 2.08 ERA in 16 career postseason appearances. He is 2-0 and allowed four hits and two runs over 10.2 innings pitches over two appearances this postseason, including a win over the Rangers in Game 3 of the ALCS.
The Philadelphia Phillies (3-2) will host the Arizona Diamondbacks (2-3) in Game 6 of the National League Championship Series at 5:07 p.m. Monday in Philadelphia.