HOUSTON -- Braxton Garrett executed the plan. Before the game, Marlins manager Don Mattingly laid out the plan for his starter: Go five innings and keep the Marlins in the game. 

The 24-year-old did that and more, allowing one unearned run on six hits with five strikeouts over 5 1/3 innings in a 5-1 win over the Astros.

“He was really good,” Mattingly said. “Just showing that his mix is good enough. He’s a guy that is able to add and subtract a couple of breaking balls, can make the fastballs a couple of things. If he is getting ahead in counts and getting the ball where he wants to, he’s got some weapons.”

Garrett made his season debut in his last outing against the Giants on June 5. The southpaw tossed three scoreless innings until one pitch changed it all -- a hanging slider that Giants shortstop Donovan Walton belted for a fourth-inning grand slam.

The task on Saturday did not look to be any easier for Garrett, who was up against an Astros lineup full of hot hitters, including Yordan Alvarez, who entered Saturday leading the league in batting average, slugging percentage, OBP and OPS since May 29.  

Garrett did not back away from the challenge, as he retired 10 of the first 13 batters he faced. He kept the Astros’ bats quiet all day including Alvarez, who went 0-for-2 with a walk against him.

The lone blemish for Garrett came in the fifth inning when a double by Jose Altuve scored Jeremy Peña, who had reached on a throwing error by third baseman Jon Berti.

A key part of Garrett’s success has come from getting ahead in the count. The lefty recorded 18 of 24 first-pitch strikes (75%), his third-best mark across 11 MLB starts. 

“For me, being a soft throwing lefty, I can’t be just around the zone,” Garrett said. “I have to get in there and be confident with what I have and get to work. Strike 1 is the best pitch in baseball, that’s for sure.”

Garrett continues to improve from when he made his MLB debut with the Marlins in 2020. He has been back and forth between the Minors and Majors in parts of the past two seasons, logging a 4.97 ERA across 12 MLB appearances (11 starts).

Garrett spent the offseason fixing points of his game like his posture, but the biggest change was changing his slider. It has become another weapon in his arsenal with a four-seam fastball, sinker, changeup and curveball already at his disposal.

Garrett relied on his new pitch frequently in his last start, throwing it 37.5% of the time against the Giants. The approach was different on Saturday with the slider usage going down to 33.7%. 

“We kept a good mix,” Garrett said. “My sinker has been really getting me out of some spots [against] lefties. I got their big boys Alvarez and [Kyle] Tucker. Again, the slider has been really good. I changed the grip and have been able to do more with it than I have in the past. I think that was the real key.”

The run support came early for Garrett as the Marlins struck early, scoring four runs in the first three innings. Miami manufactured runs any way it could Saturday, from scoring a run on a bases-loaded walk to situational hitting to create a comfortable lead over Houston.

Garrett’s performance was pivotal as questions remain about the starting rotation, which has a combined 4.40 ERA outside of Sandy Alcantara and Pablo López.

There is a lot of uncertainty with Jesús Luzardo and Cody Poteet on the IL, and some questions remain on López, who left Friday’s series opener with a right wrist contusion, though X-rays came back negative. Garrett’s development will be key in the Marlins’ stretch of 10 road games in 11 days.

“His first two outings have been really good,” Mattingly said. “You haven’t seen a lot of hard contact as he has had teams off balance. Now, you’ve got to gain consistency and, in this league, it’s tough. They will keep making changes on you, and you’re going to have to make adjustments, but being consistent is key.”