DRESDEN, Germany -- Lauren Cheney and Rachel Buehler each scored second-half goals, and the United States opened play at the Women's World Cup with a 2-0 victory over a young but scrappy North Korea on Tuesday.

After peppering North Korean goalkeeper Hong Myong Hui all afternoon, Cheney finally broke through in the 54th minute on a header. Buehler got the second goal of her career in the 76th minute, scoring on a thunderous right-footed strike that rolled beneath the outstretched hand of the diving Hong.

When the final whistle sounded, the U.S. reserves ran onto the field to celebrate while the North Koreans stood just beyond midfield, watching. It was the fourth straight time the teams had met in group play at the World Cup, and the Americans have won all but one of the games.

Still, the victory isn't likely to end the questions about the two-time World Cup champions, who have been uncharacteristically inconsistent lately. After going more than two years without a loss, they dropped three games in five months, and looked decidedly unsettled against the North Koreans for much of the first half.

"It's always good going forward," U.S. coach Pia Sundhage said. "Two great goals, and we're moving on."

Despite their World Cup "reunions," the previous games against North Korea were of little help to the Americans here. Only two of the North Koreans had played in a World Cup before, and just five had made more than 10 appearances with the senior national team.

Heck, 10 of the North Koreans were playing in the Under-20 World Cup just last year.

The mystery surrounding the North Koreans had been a concern for the Americans -- and rightfully so. The U.S. controlled the game early with crisp passing and good speed. But the North Koreans gained confidence as the game went on, and the U.S. was lucky to escape with the game tied 0-0 at the half.

Their adjustments at halftime paid off, with the Americans dominating possession and chances.

Cheney was in Hong's face so often the North Korean goalkeeper will be having nightmares about the American for weeks, even though most of her shots found their way into Hong's hands.

There was little she could do about Cheney's goal, however.

Abby Wambach, who had put a shot over the goal from the edge of the 6-yard box three minutes earlier, dribbled quickly up the left flank and took a step as if to move inside, spinning a North Korean defender around. She dribbled a few more steps before chipping in a perfect cross that Cheney nodded past Hong.

It was Cheney's 14th goal in her 40th appearance for the United States.

Wambach hit the crossbar in the 65th and Amy Rodriguez put a shot wide in the 73rd before Buehler scored the insurance goal. With the Americans packing the box, Carli Lloyd collected a pass and headed it to Buehler, who let the ball settle before unleashing a monster shot. Hong dove and stretched out her hand, but she never got close as the ball rolled into the net.

It was the second goal for the defender.

North Korea's best chances came late in the first half. Song Jung Sun slid a shot right in front of the goal in the 38th minute that Hope Solo couldn't get a hand on. No other Americans were there to clear it away -- but no other North Koreans were, either, and Ali Krieger finally booted the ball to safety. Jo Yun Mi, who led North Korea to the Under-20 title in 2006 and was named North Korea's "best footballer of the year" earlier this year, had another chance five minutes later.

North Korea had one more opportunity in stoppage time, but Yun Hyon Hi's shot was well wide of the net.