HOUSTON -- It’s not an understatement to label Wednesday’s 2-1, come-from-behind win over the Orioles at Minute Maid Park as the biggest victory of the season for the Astros, especially considering both teams on their heels in the American League West -- the Rangers and Mariners -- kept the pressure on the front-runners by winning as well.

More than anything, the style in which the Astros won -- on a walk-off single in the ninth inning by Mauricio Dubón -- is the type of victory that can create momentum. And the Astros sorely need momentum heading into the final nine games of the season, including a weekend series at home against the 100-plus-loss Royals.

"We needed this win,” Dubón said. “From now on, the mindset is ‘Win every game.’ We started today like this, so let's finish together here."

• Games remaining (9): vs. KC (3), at SEA (3), at AZ (3)
• Standings update: The Astros (85-68) lead the AL West by a half-game over the Rangers (84-68), who beat the Red Sox on Wednesday, and a half-game over the Mariners (84-68), who beat the A's. The Astros hold the season tiebreaker against the Rangers, but not the Mariners.
• Magic number to clinch AL West: 10

The Astros were trailing, 1-0, entering the eighth inning before Jeremy Peña delivered a huge RBI double off Mike Baumann to tie the game at 1. Rookie catcher Yainer Diaz began the ninth with a bloop RBI double off Danny Coulombe and scored from third on Dubón’s line drive single to right, igniting a celebration.

“That was a big one,” Astros manager Dusty Baker said. “It's nice to see the guys happy and partying, because it's been a morgue in there the last couple of games."

Peña and Dubón came through with the big hits, but there were heroes in every corner of the clubhouse. Cristian Javier, flashing the kind of fastball he had in the first half of the season, struck out a season-high-tying 11 batters in five innings, and the bullpen was nails. Bryan Abreu covered four outs, and Ryan Pressly threw a 1-2-3 ninth.

“It’s a big win,” Pressly said. “Obviously, you’re going to see that team in the postseason, so it’s a big win for us. We’ve got another big series coming up against Kansas City and we need to take advantage of the opportunities and put up some more wins at home.”

The Orioles and Astros are currently the top two seeds in the AL playoffs, and both teams appeared to drop hints of a possible rematch in October.

“They’re the defending champs over there, so we know what they’re capable of,” Orioles second baseman Adam Frazier said. “Everybody knows that, though. There’s a good chance we’ll see them again in a couple of weeks. Until then, we’ve got to finish strong.”

While the Mariners and Rangers meet each other seven times in the season’s final 10 games, the Astros aren’t taking the Royals for granted, considering they dropped two of three at Kansas City last weekend. A series win -- or better yet, a sweep -- would be massive heading into a three-game series at Seattle beginning Monday.

“We know what we have to do,” catcher Martín Maldonado said. “We have to focus on one game at a time. We just played the Royals, and we know what kind of team we are, and we have to believe in what we can do to reach our goal, to win the division.”

The biggest development Wednesday was the resurgence of Javier, who posted a 2.90 ERA in his first 14 starts of the season and a 6.99 ERA in his previous 14 starts entering Wednesday. He was pitching with confidence Wednesday and was throwing his offspeed pitches for strikes, which had the Orioles caught between the fastball and offspeed. He got 20 swings and misses, including 14 on the fastball.

“I think, for me, it was really effective like last year,” Javier said about his fastball. “I was able to get a lot of swings and misses and dominate inside the strike zone.”

An effective Javier to put behind Justin Verlander and Framber Valdez atop the Houston rotation would set the Astros up nicely to make another long playoff run in October. But first, Houston has to get there. And pulling out Wednesday’s win over Baltimore was critical.

"We got three more games [at home] and hopefully we can close out over .500 at home,” Baker said. “And then we take it to the road and maybe pick up some ground this week. If we just win, we'll pick up on somebody here.”