Lydia Ko is in total control at the halfway mark of the CME Tour Championship.

Total control of the season-long scoring and money races, too.

Ko shot a six-under 66 in Saturday’s second round of the LPGA Tour’s season finale, pushing her to 13-under for the tournament and five shots clear of Hyo Joo Kim through 36 holes.

Ko made four birdies in a six-hole stretch midway through her round, rolled in a testy four-footer to save par on the par-four 13th to maintain what was then a four-shot lead, and hasn’t dropped a shot since her opening hole on Friday.

“I stayed really patient out there,” said Ko, who turned a one-shot lead entering Saturday to a five-shot edge when it was over. “Not bogeying the first was a better start than yesterday. But with the wind direction being pretty similar and the strength being similar, I already knew going into the day that it could be tricky, but at the same time because I played really solid in the back nine, I knew that if I did make any mistakes, there were birdieable holes coming in.

“That’s kind of the goal for me this week is not let one hole or one shot phase me. This is the last tournament of the season. It’s my ninth year on tour, so I want to finish the season well and also just want to finish it without any regrets.

“I shot a low one yesterday and that round, it can be anybody throughout the week.”

Except right now, it’s not anybody else going as low as Ko has.

Ko’s 66 was the round of the day Saturday; four other players shot 67′s. Through two rounds at Tiburon, there have been four scores of 66 or lower; Ko has two of them after an opening 65 on Friday.

Kim (69) made back-to-back birdies on 16 and 17 to get to eight-under, alone in second. World No 1 Nelly Korda (69) is in a pack tied for third at seven-under, along with Japan’s Nasa Hataoka (67), Sweden’s Anna Nordqvist (69) and Scotland’s Gemma Dryburgh (70).

Korda was making a move on the front, closing her first nine with three birdies in a four-hole stretch. But she made nothing but pars on the back nine.

“Lyds is playing well. She’s had an amazing year,” Korda said. “To catch her I’m just going to have to play aggressive and drain the putts.”

And even that might not be enough. Everyone is chasing Ko, who is chasing trophies and more.

Ko entered the week with a one-point lead in the race for LPGA Tour player of the year. She needs to avoid just all-out disaster on the weekend to win her second consecutive Vare Trophy for having the year’s lowest scoring average. Those titles would move her closer to the LPGA Hall of Fame.

And with US$2 million, the biggest single prize in women’s golf, awaiting the winner, that means the money title is within her reach as well.

If Ko wins the tournament, she’d push her earnings for 2022 to US$4,364,403 (NZ$7,121,732) and virtually lock up the money title.

With Ko back at the peak of her powers, she was asked if she is a better player now than when she was world No 1.

“I hope so,” Ko said with a smile. “I hope so because it’s seven years from then.

“But my mom does joke to me at times. She’s like, ‘you played so much better when you were, like, 15.’

“I was like ‘thanks, mom.’ What am I meant to do with that information?

“I do know that I am more experienced now. Wiser? I don’t know about that, but I am playing differently. I hit it a little bit further than then.

“I’m sure there were parts then when I was younger and even in 2015 that I was better at, and some parts that I have improved over that time. But it’s just trying to bring it all together.

“Everybody has improved, and it’s hard to even keep your card because the level of play is just so good. To win it’s a whole new level.

“I do hope I’m better, and I do hope my mom is joking when she says I played better when I was 15.”