Irish golfers Shane Lowry and Graeme McDowell fired an eight-under par 64 on Saturday to join Sean O'Hair and Steve Stricker atop the leaderboard at the QBE Shootout in Naples, Florida.
The only internationals in this year's edition of the 24-player team event, Northern Ireland's McDowell and Ireland's Lowry opened with an eagle at Tiburon Golf Club and added six birdies in the modified alternate shot round to join overnight leaders Stricker and O'Hair on 18-under par 126.
Stricker and O'Hair combined to card a 69 in blustery, soggy weather.
Keegan Bradley and Brendan Steele posted a 70 and were in solo third on 16-under 128.
Lexi Thompson, the only LPGA player in the field this year, and teammate Tony Finau fired a six-under 66 to put themselves in contention three shots off the lead.
"Alternate shot is a very tough format," Thompson said. "But I knew if I had Tony on my team and he could hit some of those tee shots out there we would be taking his ball for the most part."
Thompson and Finau could find it tough to gain ground on Sunday, however, when the final round's better ball format will require Thompson to play her own ball and the men's greater length off the tee puts her at a disadvantage.
The better ball format should suit McDowell and Lowry, who played together representing Ireland in the 2016 World Cup of Golf.
Lowry and McDowell moved up the leaderboard with their eagle three at the first hole. They added three more on the front nine before McDowell holed a 15-foot birdie putt at the 10th.
After a birdie at 13, McDowell birdied 15 after Lowry's superb approach shot. One off the lead when their round ended, the two gained their share of the lead when Stricker and O'Hair bogeyed the 17th.
"It's going to be a good day tomorrow," Lowry said. "Hopefully the weather's a little better and we can go out and make some birdies and give ourselves a chance."