MONTREAL: The United States reached the final of the women's football World Cup for the second time in a row on Tuesday, taking advantage of a dubious penalty to beat top-ranked Germany 2-0 in a hugely enjoyable game.

Captain Carli Lloyd converted her spot kick in the 69th minute after the Romanian referee ruled that Annike Krahn had obstructed Alex Morgan. Replays showed the offence clearly took place outside the box.

Substitute Kelley O'Hara flicked the ball home from close range in the 84th minute to seal a merited victory in front of a passionate Montreal crowd of more than 51,000, most of them Americans.

The United States - who lost in the 2011 final to Japan - will meet the winners of the Japan and England semi-final in Vancouver this Sunday.

The Americans rode their luck in the 63rd minute when Germany's Celia Sasic missed a spot kick of her own.

US defender Julie Johnston was adjudged to have dragged down Alexandra Popp but escaped with just a yellow card.

Germany, who had to play 30 minutes of extra time in their quarter final against France last Friday, were sluggish from the start and rarely threatened the inventive fleet-footed Americans.