Tani Costa scored both of the game's goals to help the Kalani High School girls soccer team defeat 'Aiea, 2-0, last night in the quarterfinals of the O'ahu Interscholastic Association playoffs at John Kauinana Stadium at Mililani High School.

The Falcons (12-0-1), the top seed out of the East, will face Mililani in tomorrow's 7 p.m. semifinal at Kailua. Pearl City plays Kaiser at 5:15 p.m. in the other semifinal.

Pearl City beat Kahuku, 3-1, and Kaiser beat Kapolei, 1-0, in yesterday's other quarterfinals. Teams that won yesterday earned four of the league's six state tournament berths.

Costa, a junior, scored both goals in the second half.

"Even after the first half, I wasn't worried," Kalani coach Myles Arakawa said. "We were playing well. I felt it was a matter of time."

Costa scored eight minutes into the second off an assist from Kiah Fujita.

"I thought we had a lot of opportunities but we didn't capitalize," Costa said of the first half. "We just had to execute on putting it away better.

"We did a lot better with the execution (in the second half)," Costa said. "We did a lot of quick passes. We played a little more aggressive, I thought, and followed through."

In the 59th minute, Kalani goalkeeper Yasmina Taketa was whistled for picking up the ball when a teammate passed it back.

'Aiea got an indirect free kick off the call, but Costa stole the ball from the top left corner of the box before 'Aiea could get a shot off.

Na Ali'i (6-7-0), the fourth seed out of the West, had their best opportunity in the 64th minute when a cross was sent into the box from the right. Jacquie Watkins' header went off the top of the crossbar, but the ball was sent back out. Leah Peters-Valdez took a shot, but Taketa caught the ball.

Costa scored in the 66th minute from the top of the box to make it 2-0.

"We're trying to find her indirectly and I think that's slowly coming around as we work on it more and more," Arakawa said.

'Aiea was playing its second game in as many days after beating Castle in a shootout on Monday. 'Aiea coach Wanette Shirafuji tried to counter any chances of fatigue by substituting.

"We knew they would have fresh legs and we wouldn't so we subbed more often to keep them fresh," Shirafuji said. "The first half, we kept them 0-0, that was our intention."

Na Ali'i still can still earn a state tournament berth by winning tomorrow's consolation match.

"If they can play with the same intensity they played today, they can be very competitive on Thursday," Shirafuji said.

Notes: Earlier this month, Costa made the United States U-17 national team. The team will play in the World Cup in New Zealand later this year, and since the World Cup roster can change after matches, Costa said she'll keep working hard. She leaves for a training session next week on the Mainland. Costa said she has committed to play at Penn State.

MILILANI 2, MOANALUA 0

Isabel Romero and Chelsey Goo each scored a goal as host Mililani defeated Moanalua, 2-0, in the quarterfinals of the OIA playoffs last night.

Romero scored a minute before halftime and Goo scored minutes into the second half.

"It was important to be up," Romero said of the team's halftime lead. "If not, going into the second half 0-0, it's an equal opportunity for both teams."

Romero said the lead gave her Trojans (10-3-0), the second seed out of the West, courage and motivation, a big difference from how the team started the game.

"We felt the pressure," Romero said of qualifying for the state tournament and doing well in the playoffs. "As the game went on, we calmed down until we got things going our way."

Mililani will face Kalani in tomorrow's semifinals at Kailua.

"They are well-poised," Mililani coach Ray Akiona said of the Falcons. "They're a great team. If you're not ready for them, they'll run all over you."

Moanalua (8-2-1), the third seed out of the East, will play 'Aiea in a consolation match tomorrow. The winner will receive a state berth.

Reach Stanley Lee at sktlee@honoluluadvertiser.com.