Oh, Inbee Park. This is an unstoppable march, an insatiable quest for that career Grand Slam. Her approach to the par four 16th is within no more than six feet of the pole. That'll be for birdie and the lead.

Who are you backing? Inbee Park is hunting a seventh major, level on the leaderboard with Ko Jin-young, but two holes in front of her on the course. Ko must feel like she is being hunted by the biggest animal in the women's game. Not that she's showing it, a good approach to the par-four 14th unlucky to roll through the back.

Image source, BBC Sport

Inbee Park's lightning streak with the putter comes to an end, unable to drain a long birdie shot on 15. Little one for par. She's got three to play.

Dr Mark S. Elliott: J-Y Ko playing with the enjoyment that's gold dust to any sports performance. It is meant to be fun, after all. That's why we play

Image source, Getty Images

Yep, Ko Jin-young sends it by and will have a tiddler for bogey. She puffs out her cheeks and, frankly, looks a little upset. This is not the time to crack. That's her first drop of the day. Levels, you devils, at 11 under.

It's all changing right before our eyes. Ko Jin-young has the putter out from off the green on 13, has not given it nearly enough welly and is miles short. Long one for par. We could be level at the top very soon.

Inbee Park! That is a monster eagle putt on the 14th, taking her to within one shot of the Ko Jin-young. The world number one is still in the hunt to complete the career Grand Slam. One hole behind her, Ko has missed the green. game on.

Image source, BBC Sport

Oooohhh, Lydia Ko. That could be all she wrote for the young Kiwi. A par putt at 15 goes past on the left of the hole, meaning she's five back.

Ko Jin-young was actually in light rough on the 13th. There was an element of peril in her second shot, but she's OK, in decent position to get up and down in two.

Inbee Park won't make it easy for her fellow Korean, she's on the green at the par-five 14th. Long one for eagle to come.

Image source, AP

Ko Jin-young, remember, has not dropped a shot all day, with an eagle and two birdies in her first 12 holes. She has found the fairway on 13. It's hers to lose, rather than someone else's to win.

American Cristie Kerr, who finished on -1: "It was very, very challenging. I had trouble on the greens which is usually the strong point of my game. I'm happy to be done.

"The Koreans are so talented, they practice 10 hours a day. There is no shortage of talent there."

Image source, BBC Sport

Thanks, Phil. While I've been away, Ko Jin-young has surged towards winning a major at the very first attempt. Can anyone stop her now?

The leader stays at 12 under with a wayward putt at 12 that spurns the birdie chance but offers an easy par putt. The lead remains three. And with that I hand you back to Stephan Shemilt, who will see you through to the conclusion.

Maureen Madill
BBC TV on-the-course commentator

"It might be too little, too late, but Lydia Ko is still there."

Image source, Getty Images

Inbee Park won't give up the ghost. She salvages par at the 13th to stay nine under. Lydia Ko sinks one a birdie putt from 15 feet at 14 to move back to seven under.

Ko Jin-young is bang on the money with nearly every shot. It is relentless. She plants her second shot at the 12th on to the green and about 10 feet from the hole. That'll be another birdie chance.

Peter Alliss
BBC Sport commentator

"It is the chasing pack that are dropping shots here and there. The leader has played beautifully, holing some crucial putts."

Inbee Park hasn't given up hope of a career grand slam just yet, but she has work to do. The world number one's second shot at the par-four 13th is just short of the green. Disappointing.

Image source, Getty Images

Another birdie for Wales' Amy Bouden at 14 takes her to five under. She won't be threatening at the business end but she can still finish strong over this back nine.