ARLINGTON -- Considering how badly the Astros had to scratch and claw to put themselves in position to win Monday against the Rangers, the way they wound up losing -- and the opponent they lost to -- made it about as gut-wrenching of a loss as they’ve suffered this season.

The struggling Astros were one out away from taking the first game of the Lone Star Series at Globe Life Field before Josh Smith of the Rangers clubbed a two-run, two-out walk-off homer in the 10th inning off new reliever Caleb Ferguson to send Houston to a crushing 4-3 loss in 10 innings.

The Astros have lost three games in a row and six of their past eight to fall 1 1/2 games behind the first-place Mariners in the American League West race.

“We scraped [across] a couple of runs, and it looked like at the end it was going to be enough, but yeah…” manager Joe Espada said. “We’re trying to grind through it. We needed a big hit and we didn’t get it today.”

The Astros were 1-for-9 with runners in scoring position, including 1-for-7 with the bases loaded and five strikeouts. They scored twice with the bases loaded but didn’t exactly crush the ball: Jeremy Peña had an infield single in the eighth and then drove in a run when he was hit by a Kirby Yates pitch in the 10th, putting them ahead, 3-2.

Ferguson, the lefty acquired a week ago in a trade with the Yankees, struck out the first two batters he faced before Smith, a left-handed batter, crushed a 3-1 fastball and sent it a Statcast-projected 410 feet over the right-field wall for the game-winner.

“Just tried to get it away and it leaked back middle on me,” Ferguson said. “A team in contention and you get over here and want to make good first impressions and I made a bad pitch. Forget about it and move on to tomorrow.”

After the Astros took a 2-1 lead in the eighth on Peña's infield single with the bases loaded, Jake Meyers and Trey Cabbage followed with bases-loaded strikeouts. Corey Seager hit a game-tying homer off Ryan Pressly in the bottom of the inning.

“That’s baseball,” said Astros third baseman Alex Bregman, who hit a solo homer in the third inning. “Sometimes you got to tip your hat. Seager took a really good swing on a good pitch and Smith took a great swing, as well. You just tip your hat and move on to the next day and come back and continue to compete.”

Peña drove in the go-ahead run when he was hit by a pitch in the 10th, but the Astros couldn’t add on. Meyers struck out with the bases loaded and Cabbage grounded out. The Astros left 11 runners on base. They are slashing .193/.270/.287 with five homers in their past eight games, including hitting .140 (8-for-57 with 22 strikeouts) with the bases loaded.

“Lineups go through stretches where stuff like that happens,” Espada said. “We’re going through that stretch where we’re just not getting the big hit, we’re not getting the solid contact when we need to.”

Houston must win the final two games of the series against the Rangers to win the head-to-head matchup, which came into play last year when the Rangers and Astros both won 90 games and Houston took the division title on the tiebreaker.

“I didn't really know that, but every game down the stretch is big,” Bregman said. “We know that. Just show up to the yard ready to compete and prepare the right way and go out and play.”

Astros starter Hunter Brown rebounded from a rare subpar start Tuesday against the Pirates and held the Rangers to one run and three hits in six solid innings, continuing Houston’s run of strong starting pitching (2.38 ERA in past four games). But with Houston’s offense in a deep freeze, the starters have little margin for error.

“We’ve got a bunch of great guys in this clubhouse that are grinding every day, so we just didn’t come out on top tonight but that doesn’t say that we won’t tomorrow,” Brown said.