HOUSTON -- It became evident early in the season that Astros manager Joe Espada wasn’t going to be afraid to use his bench, whether it’s sending someone to pinch-hit in the sixth inning of a tight game or deploying an outfielder for defense in the final inning to help preserve the lead.

The bottom line is that if you’re not in Espada’s starting lineup on any given day, stay ready.

“If we don’t start, it doesn’t mean we’re not playing that day,” superutility player Mauricio Dubón said. “I think that’s been pretty clear the whole year.”

Espada used every position player available on his bench -- along with his three best high-leverage relief pitchers -- to pull out an improbable 6-3 come-from-behind win over the Royals on Thursday night at Minute Maid Park in one of the most clutch wins of the season.

The Astros scored four runs in the eighth inning, including a bases-loaded walk with two outs by Zach Dezenzo -- the rookie who pinch-hit in the seventh -- and a two-run single by Dubón, who also came off the bench in the seventh to pinch-hit and, like Dezenzo, struck out. They got another shot an inning later and came through to send the Astros four games up over the Mariners atop the American League West.

“Having pieces that you can go to and you trust allows me to make those moves, and guys being prepared and embracing their roles,” Espada said. “Be ready because I’m going to use you. I’m not afraid to use anything.”

A two-run double by newcomer Jason Heyward in the fifth inning gave the Astros a 2-0 lead they carried into the seventh behind starter Hunter Brown, who allowed two runs (none earned) in 6 2/3 innings. But a three-run bloop double by Kyle Isbel in the seventh negated all that good work and put the Royals ahead, 3-2.

That’s when Espada’s managerial wheels began to turn.

The Astros were already a player short on their bench entering the eighth because rookie Shay Whitcomb was forced into the game in the fifth after Alex Bregman was ejected. He took three called strikes from Brady Singer, two of which the Astros contested were balls.

“When Alex argues balls and strikes, 99 percent of the time he’s right,” Espada said.

In the eighth, the Astros sent nine batters to the plate, but this was anything but a conventional come-from-behind rally. It started, of course, with a Jose Altuve walk, and a pinch-hit single by Victor Caratini put the tying run in scoring position. Caratini is 7-for-15 as a pinch-hitter this year.

Yainer Diaz hit a grounder off pitcher Lucas Erceg, who kicked it away from the mound to allow Altuve to score from second. Erceg and Royals first baseman Vinnie Pasquantino were both injured on the play and left the game.

With the bases loaded and two outs, Dezenzo fell behind in the count, 1-2, against reliever John Schreiber before taking three straight sliders to draw a walk.

“I swung from the on-deck circle at a couple of those sliders,” Dubón said. “It’s a kid coming in on a big stage and ended up winning the game for us. He kept the line moving.”

After striking out in the seventh, Dezenzo dug deep with the bases loaded in the eighth and told himself to breathe.

“Chasing a few strikes in my first at-bat in the seventh, I wanted to make sure to do a little bit better for the team in the [eighth] and I was able to get the job done,” he said.

Dubón followed with a two-run single, and the Astros turned the ball over to closer Josh Hader, who pitched a 1-2-3 ninth to extend his club record to 29 consecutive saves. And it was Dezenzo, appearing at third base for the first time in the big leagues, who made a diving stop on Salvador Perez's grounder to start the ninth and throw to first for the out.

Be ready.

“For a young player to have the presence and the capabilities to stay calm and understand the magnitude of that at-bat and get that walk, that was big,” Espada said.

“Dubie, another big knock. These guys, they like big moments like that. Huge win there.”