HOUSTON -- After five shutout innings from ace Kyle Gibson and an early lead from the offense, the Rangers seemed to be in prime position to finally take a game in Houston from the Astros.

But a blown save by Josh Sborz, who filled in with Ian Kennedy on the 10-day injured list with a right hamstring strain, caused the Rangers to fall, 6-3, in 10 innings Tuesday night. The Rangers have now lost six straight, and 18 of the last 20, at Minute Maid Park.

Texas had a 2-0 lead after six innings, but the Astros cut the lead in half on a sacrifice fly from Yuli Gurriel. With Sborz one strike away from the save and the win, Houston shortstop Carlos Correa drove a slider on the outside corner of the zone over the right-field wall to tie the game at 2 in the ninth inning and send the game to extras.

Manager Chris Woodward said it was only one mistake from Sborz, but acknowledged that he can’t make mistakes against a quality hitter like Correa in a high-leverage situation. 

The Rangers scored one run in the top of the 10th, but Jose Altuve hit a walk-off grand slam off Rangers rookie Demarcus Evans in the bottom half of the inning to secure the win for Houston.

Evans walked the first two batters of the inning to load the bases with no outs, but Woodward was visibly upset with home-plate umpire Jerry Meals after Jason Castro’s at-bat, just before Altuve’s grand slam.  

Meals called two borderline pitches -- the first and last of the at-bat -- balls. Woodward acknowledged the loss isn't on the umpire as a whole, but he felt the situation could have changed the outcome of the game

"It's frustrating,” Woodward said. “It's a strike. I don't normally talk about umpires making bad calls, but that ball was in the strike zone. But Demarcus knows he's got to be better. You’re not going to get too many borderline calls if you’re not in the strike zone for the first seven pitches.  

“That’s not why we lost, obviously, but it had something to do with it. That’s a little bit of youth right there. The situation just sped up on [Evans] a little bit.”

The loss came on the heels of a quality start and six innings of one-run ball from Gibson, along with three shutout innings from relievers Spencer Patton and Brett Martin.

The Rangers' ace dealt six innings, allowing just one run on seven hits. He started the game with five shutout innings before allowing three hits in the sixth. In his last inning, Gibson worked his way through a bases-loaded jam after taking a scorching liner at 95.8 mph exit velocity off his calf. After giving up a sac fly to score a run, a groundout ended the inning with minimal damage.

Gibson said that while getting out of that jam ultimately didn’t matter by the end of the game, it was huge at the time.

“In the grand scheme, obviously, it didn't work out, but I think any time when you're on the road, going into the ninth inning and your offense doesn’t have to battle back, that's a good thing,” Gibson said. “I think in the moment, it’s big. We trust our bullpen. We trust those guys out there, and we’ll take our chances 2-1 going into the ninth inning.”

Gibson has been nearly flawless since returning to the rotation from the injured list on June 4. He has allowed just three runs 17 1/3 innings, including a shutout outing in a win against the Rays on June 4. Tuesday’s start lowered his ERA to 2.09 on the season.

“It all comes down to plan,” Gibson said. “Our staff and [catchers Jose Trevino and Jonah Heim] are always prepared, and we’re making adjustments when we need to.”