SHANGHAI, China — Hawaii athlete Natasha Kai headed in an extra time goal, giving the defending champion United States a spot in the Olympic women's soccer semifinal with a 2-1 victory over Canada.

Kai is a former Kahuku High School and University of Hawaii star who started the first game for the U.S. but then came in as a substitute thereafter.

U.S. head coach Pia Sundhage began overtime by bringing on Kai for Heather O'Reilly and dropping Angela Hucles back into the right midfield slot.

Minutes later, the move paid off as Kai stuck her close-range header past Karina LaBlanc.

The goal evolved as Amy Rodriguez dropped a pass back to Shannon Boxx on the left wing. Boxx hit a first time, left-footed cross that curled directly into the path of Kai, who stayed onside to beat her flat-footed marker to the ball four yards out, sending a bullet header under LeBlanc and into the left corner.

Hucles gave the Americans a 12th-minute lead with a goal from in close at Shanghai's Olympic Stadium on Friday.

But Christine Sinclair countered in the 30th for Canada with a powerful 22-meter shot.

The game was suspended for one hour and 40 minutes during the first half because of lightning.

The U.S. will now face Japan in the semifinal match at Beijing Workers Stadium on Monday, Aug. 18 at 3 a.m. Hawaii time on Universal HD and the NBC Olympic Soccer Channel. Fans can also follow online via ussoccer.com's MatchTracker.

The USA defeated Japan just six days ago by a 1-0 score in Group G play. It was the second game of the Olympics for both teams.

ussoccer.org contributed to this report