The World Series has been forced to a seventh and deciding game after the Washington Nationals scrapped their way to a 7-2 conquest of the Houston Astros.

Hosts the Astros were ahead 3-2 in the series before Tuesday's game and just needed one more win to lift the Commissioner's Trophy.

But the visitors had other ideas, courtesy in large part of another powerhouse performance from pitcher Stephen Strasburg, who was dominant through more than eight innings.

The 31-year-old sent a hush around Minute Maid Park when he struck out Jose Altuve in the fifth.

Another turning point came moments before when Washington took a 3-2 lead after Juan Soto slugged his third homer of the World Series and cheekily carried his bat all the way to first base.

The final game will be played in southern Texas on Wednesday.