HOUSTON -- All the hallmarks are there to confirm the Seattle Mariners as an improved team, from the diversified offense to the quality starting pitching to including a willing and able bullpen eager to contribute to the positive momentum generated out of the All-Star Game break.

Left-hander James Paxton continued his exceptional pitching this month and Ben Gamel provided support with a two-run home run as the Mariners won the rubber match of their three-game series with the Houston Astros 4-1 on Wednesday at Minute Maid Park.

Paxton (9-3) extended his winning streak to four consecutive starts with another dominating performance against the Astros (63-32). He allowed one run on six hits and one walk with seven strikeouts over seven innings, improving to 2-0 with an 0.45 ERA over three starts against Houston this season. Paxton has 20 strikeouts versus four walks against the Astros in 2017.

"I just felt really good," Paxton said. "I was throwing the curveball for strikes, moving the fastball around, mixing in some cutters, too, a few changeups. Everything was just feeling really good and Z (Mariners catcher Mike Zunino) did a great job of calling the game back there."

The Mariners (48-48) didn't mount an overwhelming offensive attack against Astros right-hander Charlie Morton (7-4), but they did capitalize on the opportunities that were presented.

Morton set down the first nine batters he faced, but Gamel followed a leadoff single by Seattle shortstop Jean Segura, who finished 2-for-4, in the fourth inning with his fifth home run, a line drive to right field that gave the Mariners a 2-1 lead.

Seattle loaded the bases with no outs in the sixth inning but Morton escaped allowing just one run on a Robinson Cano fielder's choice groundout that scored Guillermo Heredia. Zunino chased Morton with a run-scoring double with two outs in the seventh, plating Danny Valencia.

"I think fastball command was better today," said Morton, who allowed four runs on six hits with five strikeouts in 6 2/3 innings. "I actually thought my curveball and my changeup was pretty good. Just there were some situations where I needed an out and I didn't make a pitch."

The Astros' lone tally came in the third inning when Alex Bregman opened the frame with a leadoff single, advanced to second base on a Jake Marisnick bunt, and added a steal of third before scoring on a sacrifice fly by George Springer.

When the Astros threatened in the eighth inning, Heredia turned in a marvelous defensive play, receiving a carom off the left-field wall before firing a strike to third base to nab Springer as he tried to advance on a Jose Altuve single.

"Oh, unreal, what a play," Gamel said. "It's everything, and Springer can run too, so it's not like there's a slow runner on first base. He (Heredia) had to be perfect and he was."

Mariners manager Scott Servais added: "Big double by him today, scoring a run, but the carom off the wall and the throw to third base, that was the play of the game."

Edwin Diaz notched his 18th save for the Mariners, who completed a 5-1 road trip.

The Mariners could credit multiple contributors to their series victory, but it was Paxton who paved the path to their success with another performance that left the Astros utterly baffled.

"Sometimes you just have to tip your cap to the guy and move on," Springer said. "He did what he always does. It makes it a tough day for anybody."

NOTES: Astros SS Carlos Correa underwent successful surgery to repair a torn ligament in his left thumb on Wednesday. Correa, who sustained the injury in the fourth inning on Monday night, is expected to be sidelined six to eight weeks. ... Mariners OF Mitch Haniger missed his fourth consecutive game with an injured right index finger. Seattle manager Scott Servais considered playing Haniger in the series finale but opted to give him another day off to deal with lingering discomfort from throwing the baseball. Haniger will be in the lineup on Thursday against the New York Yankees. ... Astros RHP Will Harris is scheduled to play catch on Friday in Baltimore as he works his way back from a bone bruise in his shoulder that landed him on the 10-day disabled list on July 11. Harris could have his stint on the DL pushed beyond 10 days.