HOUSTON (AFP) — Yordan Alvarez blasted another game-winning home run as the Houston Astros defeated the Seattle Mariners, 4-2, to take a commanding 2-0 lead in their best-of-five Major League Baseball playoff series on Thursday.

After breaking Seattle hearts with a walk-off three-run home run in Tuesday's game one, Alvarez once again electrified Houston's home crowd at Minute Maid Park.

The 25-year-old Cuban slugger slammed a two-run shot off starter Luis Castillo into the left field seats in the sixth inning to transform a 2-1 deficit into a 3-2 lead.

That 371-foot blast changed the momentum of the game and ultimately set up victory for the Astros, who are chasing a fourth World Series appearance in six seasons since their 2017 victory.

Astros shortstop Alex Bregman singled to right field in the bottom of the eighth inning to score Jeremy Pena for an insurance run.

Astros skipper Dusty Baker paid tribute to Alvarez's temperament after his latest home-run salvo.

"He's a big boy and I call him 'Grande,'" Baker enthused.

"He comes up big. We love having him at the plate. He likes to be in the big moment."

"His concentration and discipline are way ahead of his years. We just love having him."

Alvarez, meanwhile, gave an insight into his mental approach at the plate after the victory.

"I just try to disconnect from everything when I go up there to the plate," Alvarez said.

"I try to go in there with a plan of attack, try to visualize everything."

The Astros now need just one win from the remaining three games of the American League Division Series to advance to the AL Championship Series against either the Cleveland Guardians or New York Yankees.

The Astros initially took the lead in the second inning when Kyle Tucker homered off Castillo into right field.

But Seattle tied it up in the top of the fourth when Eugenio Suarez scored after Carlos Santana reached on a fielder's choice.

Seattle right fielder Dylan Moore then singled to drive in Mitch Haniger to put the visitors up, 2-1.