Dominican slugger Juan Soto smacked a solo home run and a two-run double to power the Washington Nationals over Houston 5-4 in Tuesday's opening game of the 115th World Series.

The 20-year-old left-fielder homered in the fourth inning and drove in the deciding runs in the fifth while left-handed closing reliever Sean Doolittle forced the final four Houston outs, inflicting the first loss on Astros starting pitcher Gerrit Cole since May 22.

Washington jumped ahead 1-0 in Major League Baseball's best-of-seven championship final, which continues Wednesday in Houston.

Soto became the third-youngest "cleanup" batter – fourth in the lineup – in World Series history after Ty Cobb in 1907 and Miguel Cabrera in 2003.

Soto, who turns 21 on Friday, admitted he was nervous in his World Series debut.

"In the first at bat, I'm not going to lie, I felt a little bit shaky in my legs, but I just tried to control my emotions and hit the ball," said Soto.

"After the first at bat I just said it's just another baseball game. Just go out and enjoy."

The Nationals have won 17 of their past 19 games, including seven in a row. Game one winners have eventually taken 18 of the prior 22 World Series titles.

Cole, this year's major league strikeout leader, had won 19 straight decisions in his past 25 starts over five months, the longest one-season win streak in MLB history, but he also surrendered the most runs he has since last losing on May 22.

"He has been so good for so long, there builds this thought of invincibility and that it's impossible to beat him, which is why I want to give credit to the Nats," Astros manager A.J. Hinch said.

"It's just not easy to do what these guys do and their streaks of dominance."

The Astros seek their second title in three seasons while the Nationals, who moved from Montreal to Washington for the 2005 season, chase their first crown and the US capital's first since the Senators captured the 1924 championship.

The Nationals could join the 1914 Boston Braves as the only World Series champions who were 12 games below .500 during the regular season.

Washington right-hander Max Scherzer took the victory despite lasting only five innings, striking out seven while allowing five hits and three walks.

Houston first baseman Yuli Gurriel smacked a two-run double off the left-field wall to put the Astros ahead 2-0.

Washington's Ryan Zimmerman answered with a solo homer to centerfield in the second inning and Soto blasted a solo shot to left field to start the fourth inning to equalize at 2-2.

The Nationals seized the lead for good in the fifth when catcher Kurt Suzuki walked, took second on a Victor Robles single, reached third on Trea Turner's fly out and scored on Adam Eaton's single to right field.

After Anthony Rendon grounded into a fielder's choice, Soto blasted a two-run double off the left-field wall to lift the Nationals ahead 5-2 - the major league's best lineup at scoring with two outs in an inning producing that way once again.

Astros batters wore down Scherzer, making him throw 112 pitches in five innings, so in the sixth Washington used Patrick Corbin, a possible future starter, for a scoreless relief inning.

But the Nationals bullpen of relief pitchers, with the worst earned-run average of any playoff team in major league history, couldn't make the margin last.

Tanner Rainey entered in the seventh and surrendered a towering solo homer to Houston's George Springer and two walks. Daniel Hudson replaced Rainey but Carlos Correa singled to load the bases before Hudson struck out Yordan Alvarez to end the threat.

In the eighth, Houston's Kyle Tucker singled, took second on an Aledmys Diaz fly out and scored on Springer's double off the centerfield fence to make it 5-4.

Doolittle entered to get the last four outs, starting with Michael Brantley's fly out to Soto to end the eighth, and retired the Astros in order in the ninth for the save.