(Photo credit: Mike Lang / Sarasota Herald-Tribune / USA TODAY NETWORK via Imagn Images)

Celine Borge of Norway and Polly Mack of Germany surged to the top of the leaderboard at the halfway point of the Dow Championship as they collaborated for a 10-under-par 60 score during the second round of the Dow Championship on Friday at Midland (Mich.) Country Club.

Borge and Mack began the day a stroke back after a 2-under opening round. They took major advantage of the four-ball format -- considered the easier of the two for the team event -- for the second round, combining for a bogey-free showing to sit at 12-under 128 through two rounds.

Japanese pair Ayaka Furue and Yuna Nishimura (61) are a stroke back at 11 under while world No. 1 Nelly Korda and her German teammate Olivia Cowan (60) are next at 10 under.

The LPGA's lone team event features 72 two-woman teams. They played foursomes (alternate shot) on Thursday and four-ball (best ball) on Friday. The 34 teams that made the 36-hole cut play foursomes on Saturday and four-ball on Sunday.

Borge and Mack both did their part as they began the day on the back nine. They each tallied birdies on Nos. 12 and 17, Borge added one on the 10th hole and Mack did solo on the 14th.

Mack carried the load on the front nine, though, notching an eagle at the par-5 third hole and three other birdies. Borge didn't have any under-par holes on the front nine, but she contributed pars on the two holes Mack bogeyed.

'I feel like we are really just in sync right now,' Mack said. 'Even when one is like a little bit in trouble, the other one is making the birdie putt. It's pretty cool to see.'

The pair, both of whom joined the LPGA Tour in 2023, have no wins and only one top-10 finish between them. This is the fourth time the roommates have played together at this event, missing the cut the last two years after a T3 finish in their debut in 2023.

'We have really good memories from three years ago and we know that we can do it, so I think we're even striving for more this year,' Mack said.

Furue and Nishimura delivered six of their nine birdies in succession as they wrapped around the back nine to the front. It was a clean day for both, with the pair only scoring two bogeys in the entire round -- neither of which counted as the team's score on the hole.

'The first half, Ayaka helped out a lot,' Nishimura said. 'In the second half, I was able to contribute so I'm happy about it.

Korda and Cowan were even through Round 1 before tying for the best round of the day on Friday, pairing 11 birdies with a lone bogey they had to score on the par-4 16th. They were each bogey-free in the second half of their round, a six-under front nine.

The pairs of Gina Kim and Yana Wilson (63), Japanese sisters Chizzy Iwai and Aki Iwai (63), Sweden's Linn Grant and Maja Stark (63) and South Korea's Hye-Jin Choi and Hyo Joo Kim (62) are tied for fourth at 9 under.

Hall of Famer Juli Inkster, 66, became the oldest player to make an LPGA cut when she combined with 27-year-old Angel Yin for a 68 on Friday that elevated the duo to 3 under for the tournament.--Field Level Media