"Hopefully, we'll be able to build confidence off this win," Buehler said.
Buehler, an All-American while at Stanford, was in the right place at the right time, punching home a goal along the ground just inside the net to give the U.S. its two-goal edge.
Carli Lloyd collected a pass and headed it to Buehler, who let the ball settle before unleashing her monster shot.
UCLA grad Lauren Cheney also scored for the top-seeded Americans, who are aiming at their first World Cup title since 1999.
"These three points were very important," USA forward Abby Wambach said. "To me they felt like seven. We have a tough game against Colombia and Sweden ahead so we want to prepare for those games."
The U.S. meets Columbia at the Rhein Neckar Arena in Sinsheim, Germany on Saturday at 8:30 a.m. (PT) in its second game.
"It's always good going forward," U.S. coach Pia Sundhage said. "Two great goals, and we're moving on. I think we showed that we are ready. I want to stress how important it is to look at the next game. I really enjoyed this game and we'll prepare for Colombia."
Columbia lost to Sweden, 1-0, on Tuesday.
"It doesn't matter what happened in the past," Wambach said. "It's all about what's happening in this tournament, and that's what we're focused on."
In the 54th minute, Ali Krieger dribbled down the left and found Wambach, who cut inside and crossed with her right foot. Cheney went for the header, connected, and put the U.S. ahead.
"I think it wouldn't have mattered who scored as long as we won," Cheney said. "It's obviously a great feeling scoring goals and that's why I play forward or outside midfield because I love to attack."
The Americans outshot Korea, 19-13, including a 12-7 advantage on goal.
Buehler was one of four players who made their World Cup debut and were also members of the 2008 Olympic gold medal team. Buehler was joined by Amy Rodriguez, Ali Krieger, and Amy LePeilbet.
The U.S. needed to win a playoff series with Italy to advance into the World Cup after losing to Mexico.
The Americans also lost their most recent meeting with Sweden.
"I think the bumps in the road were good for us, they helped us improve, build on things and tighten up weaknesses," Buehler said. "This game was really great for us. We came out very unified and played with a lot of heart. I think it's a great building point and I'm excited to keep building throughout the tournament."
In another World Cup opener, Monica Ocampo scored the tying goal in the 33rd minute and Mexico came away with a point after matching England, 1-1, in the first round of pool play on Monday.
The match at Wolfsburg Arena Im Allerpark drew 18,702 fans.
Stanford junior Alina Garciamendez played the full game in the back for Mexico while Palo Alto's Teresa Noyola subbed in at the 85-minute mark.
The Mexicans had two scoring opportunities in extra time, with one shot blocked and another saved.
"We achieved a great result," Ocampo said. "We are now focusing on the next matches. I am very proud of the goal. We have a very good team and I am very proud of their support during this match."
Mexico meets Japan on Friday. The Japanese edged New Zealand, 2-1, on Monday. Stanford grad Ali Riley plays for the Kiwis.
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