HOUSTON -- The Red Sox weren’t sweating their loss to the Astros in Game 1 of the American League Championship Series. They knew they had the firepower to bounce back.

Case in point: Saturday’s historic offensive outburst.

• 9 incredible facts from Boston's Game 2 win

Not only did the Red Sox rebound to even up the ALCS in Game 2, their bats exploded to produce an all-time performance that featured grand slams by J.D. Martinez and Rafael Devers in a 9-5 victory over the Astros at Minute Maid Park.

The Red Sox became the first team in postseason history to hit two grand slams in one game. Only one other game in postseason history has seen multiple grand slams -- Game 4 of the 2005 National League Division Series, when the Astros and Braves each hit one.

“I’m really happy about making that kind of history,” said Devers. “We’re all here to give the best of ourselves. To come away with a record like that, you can’t help but feel happy about it.”

Adding to the craziness of it all: The two slams came in the first two innings. Martinez delivered the opening blow, following Alex Verdugo’s two-out walk to load the bases with an opposite-field blast off Houston starter Luis Garcia to supply Nathan Eovaldi with a 4-0 lead before he even took the mound. In the second, Devers sent a 1-1 cutter from Jake Odorizzi into right field for another slam that landed not too far from the spot where Martinez hit his.

Martinez continues to erase any concerns that might be lingering over the health of his left ankle, which kept him out of the AL Wild Card Game. The emphatic statement he made Saturday was a carryover from his success in the AL Division Series against Tampa Bay, in which he went 7-for-15 with one home run in three games.

Martinez jumped on a 1-0 fastball from Garcia, tagging it 106 mph off the bat and hitting it a Statcast-projected 363 feet. It was the four-time AL All-Star’s first career playoff grand slam and, at the time, the seventh postseason grand slam in Red Sox history, the most recent being Jackie Bradley Jr.'s at Houston in Game 3 of the 2018 ALCS.

“It's a tough spot for [Garcia],” Martinez said. “Credit to the guys before me, to Dugie and Devers, who grinded out really tough at-bats and drew the walks there to give me that chance.

“That situation, the pressure is on [Garcia], it's not on me to come through there. It's the first inning. He has bases loaded. I'm trying to tell myself that, trying to stay relaxed and just looking for a pitch so I can just put a barrel on it.”

Devers’ slam propelled him to 24 career postseason RBIs, which is tied with current opponent Carlos Correa for the most in postseason history by a player before his 25th birthday. The Red Sox third baseman turns 25 on Oct. 24.

The fact that Devers is even able to swing a bat at full speed is remarkable. It’s clear he’s not at full strength as he deals with a nagging right forearm issue. But he continues to grind away, and he has discovered an effective approach to adjusting his swing without losing too much of that power.

“He has found his routine, his cues, his thought process of what he has to do to line his swing up,” Martinez said. “It hurts me when I watch him swing and put the bat down like that. But it shows his heart. He is out there competing, and he is putting tough at-bats together. That was a really big hit.”

Of course, such a high-scoring day for Boston would not feel complete without a contribution from Kiké Hernández. Baseball’s hottest hitter continued his scorching postseason by adding to the already huge lead with a solo homer in the fourth. Hernández also doubled as part of a 2-for-4 game, giving him nine extra-base hits and 15 total hits in the last five games -- the most over a five-game span in postseason history.

After splitting two games in Houston, the Red Sox return home to Fenway Park for Game 3 on Monday. They’ll do so with an offense that is firing on all cylinders. After collecting 11 hits on Saturday, Boston has recorded 10 hits or more in each of its last five playoff games, which is a franchise record and ties the all-time postseason mark for a single year with the 2004 Astros, ‘02 Angels and 1989 Cubs.

“We have guys hitting in the top of the order and guys hitting at the bottom of the order,” Martinez said. “It's a deadly lineup because you know the guys in between are going to pretty much do what they do. Kiké to be playing the way he is playing, and even Dugie hitting the ball the way he is hitting the ball, I mean, it's just a potent lineup, one through nine.”