Charley Hull and surprising England grabbed the lead in the UL International Crown on Saturday, and the United States advanced with a sweep against Japan.
Hull, who missed Friday's four-ball session with a fever and trouble with her asthma, teamed with Melissa Reid for a 3-and-1 victory over sisters Ariya and Moriya Jutanugarn of Thailand. Holly Clyburn and Jodi Ewart Shadoff routed Pornanong Phatlum and Porani Chutichai 7 and 5, helping seventh-seeded England to a Pool B-best nine points.
"We couldn't have asked for much of a better day than we got today," Clyburn said.
The U.S., which began the day with just three points, turned in its best performance so far in the rare team event on the LPGA Tour. Lexi Thompson and Cristie Kerr posted their second straight win with a 4-and-2 victory over Ai Suzuki and Ayaka Watanabe, and Stacy Lewis and Gerina Piller surged to a 3-and-1 win over Haru Nomara and Mika Miyazato.
Taiwan also wrapped up a spot in the fourth session before a storm delayed play with two Pool A matches still on the course, leaving two spots open for Sunday's 10 singles matches. The country with the most points at the end of the weekend wins a silver trophy, to go along with $100,000 and a crown for each of its four players.
The 20-year-old Hull struggled to breathe for much of Thursday night and got some oxygen and an IV to help her feel better. She watched the back nine of Reid's gutsy effort playing by herself in a close loss to Japan, and felt "fresh as a daisy" when she showed up on the first tee for the third session.
Shaking off a slow start, Hull and Reid won five straight holes to go from two down to three up. Hull had three straight birdies before she eagled the par-5 8th. Reid closed out the string with a birdie on No. 9.
"Me and Mel both played awesome, so it was fun," Hull said.
England did not make the field for the inaugural event in 2014, won by Spain with 15 points. It was considered an afterthought coming into this week at the Merit Club about 40 miles northwest of Chicago, but the strong start has the women dreaming of what a victory could do for the sport in their country.
"You know, if we did win, hopefully it would inspire not only girls but women and men and some young guys and boys and stuff to want to take up the club and think that it's fun and want to learn how to play this game," Reid said.
The second-seeded U.S. was swept by England on Thursday, but it rebounded with three points against Thailand in the second session and picked up even more momentum against Japan. Piller finished her match with a birdie on 17, and Thompson beat the oncoming storm with a closing eagle on 16.
"We stuck with our pairings, and we just tried to stay positive with it and go out and play aggressive," Thompson said. "We knew we had to make birdies and just go for it."
Piller and Lewis were tied with Nomura and Miyazato before Piller rolled in a birdie from the fringe on 12. Piller got a good look at the putt when Lewis left one just short from right in front of her ball.
"Any time you get a free read is huge, and after she hit it, she told me what she put it at and where it ended up," Piller said.