HOUSTON -- The first inning really unraveled for Astros starting pitcher Framber Valdez, who walked a pair of hitters, committed a balk when his spike got caught in the mound, hit a batter and was basically teetering on the brink of disaster. All kinds of things started going through the mind of Astros manager Dusty Baker, and none of them were good.

While Valdez recovered and wound up delivering a quality start, Baker’s mind was put to ease when the Astros’ offense -- behind the return of slugger Yordan Alvarez -- exploded for nine runs in the bottom of the first inning to bury the Mariners, 11-1, at Minute Maid Park.

• Box score

“I don’t know what the record is for this team in the past, but you score nine runs in that first inning, and that set the tone for the game and allowed Framber to settle down,” Baker said. “We got some lucky hits this time. It hasn’t been going our way. It was a wonderful thing to see that.”

Alvarez, the 2019 American League Rookie of the Year Award winner, who missed the three weeks of the season while recovering from COVID-19, hit a 343-foot homer into the Crawford Boxes in left field in his first at-bat of 2020 to give Houston a 4-0 lead in the first. Yuli Gurriel followed with a laser to left field off Nestor Cortes, as Houston sent 14 batters to the plate in the first.

• Alvarez activated, HRs in first at-bat

“I felt really good being able to be back in the batter’s box,” said Alvarez, who added an RBI when he was hit by a pitch in the fifth. “I felt good, I felt comfortable. I wasn’t expecting to hit a home run on that exact swing, but it left.”

Martín Maldonado had a two-run double in the first inning, tying him with Alex Bregman for the team lead with 14 RBIs. Josh Reddick had three hits for the Astros as every starter had reached base by the second inning except struggling Jose Altuve, who went 0-for-5 and is now hitting .175 this season.

Reddick called Alvarez's homer a “really cool moment” and said his return felt like a second Opening Day.

“It’s a huge boost for us,” Reddick said. “Not only in the power department and driving in runs and really working counts and giving some guys some protection. ... He just brings that fear factor for us in the middle of the lineup and really helps us move our lineup along better.”

The first inning could have been much worse for the Mariners, though, as Alvarez hit into a bases-loaded double play in his second at-bat of the frame to end the outburst. Alvarez’s double-play ball was scalded at 111.7 mph, which was the hardest-hit ball of the inning.

“I felt like I really squared that ball up, which is all I can ask right now, to get my rhythm back,” he said.

Valdez settled in nicely and picked up his first win by holding Seattle to one run and four hits in six innings to deliver a quality start that lowered his ERA to 1.90.

“I don’t know exactly what happened in that first inning,” Valdez said. “I got really anxious in the middle of the inning there. I wanted everything to happen a little bit too quickly. The good news is I was able to calm down. I took a deep breath. I was able to refocus myself and get the three outs, even though I was going through a tough time in that inning. I was able to relax from there.”