Thailand's Ariya and Moriya Jutanugarn grew up playing with and competing against each other. The sisters' rivalry dates back to their days as amateurs and continues in their professional careers.
Even when the two are paired together in match play, competition with each other is what drives them.
"Before I tee off," Ariya said, "I say, 'I'm going to make birdie.' And she says …"
Here, Moriya interrupts: "No, I'm going to make birdie."
The drive to be better served the Jutanugarn sisters well on day two of the inaugural International Crown at Caves Valley Golf Club. The twosome beat Candie Kung and Teresa Lu of Taiwan on Friday, 3 and 2, for Thailand's first victory of the tournament.
Ariya and Moriya Jutanugarn were also paired together Thursday, when they halved with Spain's Belen Mozo and Beatriz Recari. Ariya struggled mightily throughout the day, especially on her drives. Moriya said it was partly due to nerves.
On Friday, both sisters opened with birdies on the par-4 first for a 1-up advantage. Ariya made par on No. 6 to push the lead to 2-up, and both sisters birdied again on No. 11 to push their lead to 3-up.
"I just tried to keep her more calm [today]," Moriya said. "We were kind of joking around, just like that, and she kept me calm, too."
Thailand ended the second day of competition with two victories that earned them four points. Their total of five points is good for first place in Pool A.
The United States — who will play Thailand on Saturday, the last day of pool play — is tied with Taiwan for second place with four points, while Spain sits in fourth with three points.
Thailand's second victory wasn't decided until Onnarin Sattayabanphot sank a 17-foot birdie putt on No. 18 for a 1-up victory with Pornanong Phatlum over Taiwan's Yani Tseng and Phoebe Yao.
"That putt, that gave me goose bumps," Sattayabanphot said. "It was all I had today. I'm really glad it went in."
Australia pair blows 6-stroke lead
Katherine Kirk and Lindsey Wright each had a chance to stop Australia's nose dive with one last putt on the day.
The pair squandered a 6-up advantage it had gained through the first 11 holes Friday against Japan's Ai Miyazato and Sakura Yokomine. But going into No. 18, Australia was just 1-up.
Miyazato and Yokomine each shot par on the par-4 18th. One par from either Kirk or Wright would have given seventh-seeded Australia the two points that come with a match victory.
Both Kirk and Wright missed their last putts of the day. They halved the match with Miyazato and Yokomine to earn one point for Australia.
"It hurts, obviously, but we can't change what's happened," Kirk said. "We can learn from it and certainly go out there tomorrow and try and make amends."
After a birdie from Wright on No. 11 put her pairing 6-up, Australia needed to win the next hole or finish the next two all square in order to shut the door early on Japan with a 6-up win.
A birdie from Yokomine on the 12th hole got things started for Japan while Australia faltered down the stretch. Kirk and Wright each bogeyed hole No. 13 and double-boyed No. 14 before bogeys on the 18th hole.
"Until 12 holes, I and Sakura [were] like, 'Today is just the Australians' day,' you know," Miyazato said. "We tried to accept the results and tried to move on.
"The one point is huge."
Earlier in the day, the Australian pairing of Karrie Webb and Minjee Lee fell to third-seeded Japan's Mamiko Higa and Mika Miyazato, 3 and 2.
Japan leads Pool B and the entire eight-team field with six points, as the only team that has yet to lose a match.
A match of birdies
There were a lot of highlighted numbers on the International Crown results board next to the match between Team South Korea's Na Yeon Choi and I.K. Kim and Team Sweden's Pernilla Lindberg and Mikaela Parmlid.
That's because there were a combined 25 birdies and one eagle between the four players of the match. Choi had eight birdies and Kim had seven birdies for South Korea. Lindberg had four birdies and Parmlid had six birdies and one eagle for sixth-seeded Sweden.
South Korea shot a 10-under 61 on the 71-par course at Caves Valley to edge its opposing Swedish pairing, 1-up. Sweden shot a 9-under 62 on the day.
"It was impressive, just playing in it and also watching the other team making that many birdies and eagles," Kim said.
With the win, Choi and Kim earned No. 2 seed South Korea two points after Sweden's Caroline Hedwall and Anna Nordqvist defeated South Korea's Inbee Park and So Yeon Ryu, also 1-up.
Hedwall posted two eagles in her round, the most of any golfer in the 32-player field.
But Parmlid's team-best 8-under round might have been the most impressive given she's five months pregnant.
"I know Mikaela is … very serious about this tournament, and she's obviously pregnant, but she says she's been walking at home." Nordqvist said. "She found out it's a hilly course, so she came prepared and she really has a great mindset this week."
After Friday, South Korea is in second place in Pool B with four points, ahead of third-place Sweden, which has three points.