It was a race against time Friday when the later players in the afternoon wave of the KPMG Women’s PGA Championship hastened to finish up their second round before darkness fell at Aronimink Golf Club.

Sei Young Kim was easily the most recognizable through all of this. She was the one that was scorching Aronimink’s front nine with birdie after birdie after birdie.

When she putted out for birdie at the par-5 ninth, her last hole of the day, around 6:30 p.m., Kim finished a 6-under-par 29 on the front nine of Aronimink for a round of 65, good for a two-day score of 4-under 136 and a 1-stroke lead in the LPGA major.

Kim, 27, carded four birdies in a row, on holes 4 through 7, along with birdies at 1 and 9 to become the first woman to post a 29 this week and tie the championship’s record for low nine holes. Karrie Webb set the mark in 2001 at DuPont Country Club in Wilmington when the tournament was known as the McDonald’s LPGA Championship, and Sarah Kemp tied it in 2011.

“The wind fluctuated on the back nine, so I struggled with my iron game,” said Kim, who is No. 7 in this week’s women’s world rankings. “But when we entered the front nine, the wind kind of slowed down and it was kind of easier to attack with my irons."

Kim’s strong finish broke a first-place logjam that dropped four players – Jennifer Kupcho, Danielle Kang, Carlota Ciganda and Anna Nordqvist – into a tie for second place at 137. Kupcho also had a 65, tying Kim for the lowest round of the championship, while Kang and Ciganda shot 69 and Nordqvist a 68.

Kelly Tan, who shared the lead after the first round, was part of a five-way tie at 138 that included Ashleigh Buhai (68), Lauren Stephenson (68), Lydia Ko (70) and Linnea Strom (70).

Kim, who has 10 career wins on the LPGA Tour but is still seeking her first major title, did not get off to a great start. She bogeyed two of her first three holes to slip to 3-over for the tournament and was closer to the cut line (6-over) than the lead (3-under).

Her first birdie came at the par-5 16th, and her birdie binge began shortly after she made the turn. She said her most memorable birdie came at the fourth hole, which kicked off her streak of four in a row.

“That was pretty good because it was a long birdie putt,” she said. “That’s when I started the four-birdie streak, so I think that really helped me with momentum and finishing strong.”

Kupcho, the runnerup in last week’s ShopRite LPGA Classic at Seaview, carded five birdies during her bogey-free round. Her performance apparently allayed her concern about being ready to take on Aronimink.

“Going into last week, I felt completely unprepared, and honestly I felt the same way coming into this week,” said Kupcho, the 2018 NCAA individual champion. “I didn’t feel like I was ready to come play this type of a golf course. I think not being prepared brings another challenge for me, and I think that’s what helps me play well.”

Ciganda is returning to good health and good form after having tested positive for COVID-19 in mid-June. She had two birdies and one bogey on the day. She likes the way she’s playing, and feeling.

“I had the virus for five weeks, and I was quite tired,” she said. “It took me like a month and a half to get back to my normal energy and to feel good again. It’s been long, but I’m happy I had it, and I’m happy that I’m playing again and feeling pretty good again.”

Notes: The cut was set at 6-over-par 146, and that was one too many for Klara Spilkova, who was assessed a 2-stroke penalty for slow play at the par-4 15th hole. The par she made at the hole became a double bogey 6, dropping her from 5-over to 7-over, and she was unable to make a birdie coming in. … Two of the top 10 players in the world, No. 2 Nelly Korda and No. 6 Minjee Lee, both withdrew from the tournament due to injuries. Korda said on Twitter that she had back soreness. Officials did not disclose Lee’s injury.