HOUSTON -- The Astros didn’t need any extra-inning heroics this time. Gerrit Cole made sure of that. So did Yordan Alvarez.

After needing a pair of walk-off hits in the 10th inning by Yuli Gurriel to win the first two games of the series against the Mariners, the Astros polished off a three-game sweep behind three RBIs from Alvarez and seven dominant innings from Cole in a 6-1 win Sunday afternoon at Minute Maid Park.

• Box score

Here are three key things from the Astros’ first three-game sweep of the Mariners since 2007.

Alvarez returns strong

Alvarez, who missed the previous two games with a sore left knee, returned to the lineup as the designated hitter and drove in the Astros’ first three runs with a bases-loaded, two-run double to right field in the first inning off Seattle starter Marco Gonzales and an RBI single in the third to score Alex Bregman, who had tripled.

“He’s a difference-maker in the middle of the order when he gets pitches to hit and hits them hard,” Astros manager AJ Hinch said. “It’s nice to have him back, obviously. He’s still not moving around great and he’s unlikely to play the field in Colorado [on Tuesday and Wednesday], but he made a huge impact today and he’ll be a big bat for us off the bench in a National League ballpark, and he provided a nice little spark for us.” 

The rookie is the fifth player in Major League history to record least 21 RBIs in his first 16 career games. 

“I’m very happy, obviously,” Alvarez said. “It’s an incredible feeling but really happy that I’ve done the work to get to this point.” 

Cole dominates 

After finding out he was headed to the All-Star Game for the third time (and second year in a row), Cole (8-5) won his fourth consecutive decision (and his seventh straight quality start) by striking out 10 batters over seven innings, allowing only a first-inning home run to J.P. Crawford.

“Crawford hit a ball that was arguably a ball out of the zone -- upper 90s -- for a homer and he settled in and was completely dominant,” Hinch said. “He executed almost flawlessly and finished his outing throwing 100. I run out of things to say about outings like this where he’s in cruise control and he’s executing. If he missed, he missed barely, and probably could have gotten a few more calls and took over the game.”

Cole recorded his ninth double-digit strikeout game -- the second-most in baseball behind Chris Sale's 10 -- and he leads the AL with 161 strikeouts. He went 3-0 with a 1.89 ERA in six starts in June, all of which have been quality starts.

“I just thought we executed a lot of pitches today,” Cole said. “The slider wasn’t going for us early, but we stuck with it and kind of sprinkled a couple of changeups in to keep them off both. When it was all said and done at the end, we had all four pitches.”

In typical Cole fashion, his 109th and final pitch was a 100.3 mph fastball he blew by Tim Beckham for a strikeout.

“I just like to leave it out there and feel like I put in a good day’s work,” Cole said.

Altuve finding his stroke

Altuve, who wasn’t named an All-Star for the first time since 2013, went 3-for-5 with a run scored and an RBI, raising his batting average to .255.

After missing 35 games due to injury, Altuve is hitting .292 (14-for-48) since being activated. It was his 141st career three-hit game, which ties him with Hall of Famer Jeff Bagwell for second-most in franchise history. 

“He’s under control of his body in the batter’s box a lot better,” Hinch said. “You see him hanging back on that back leg, which is key. He’s a really good hitter. If people are doubting him or people wonder coming to the ballpark whether he’s going to hit or not, check the back of the baseball card. He’s going to return to exactly where he’s supposed to be by the end of the year.”