Brooke Henderson struggles in 3rd round of U.S. Open

Canada's Brooke Henderson, after barely making the cut Friday at the U.S. Women's Open, began her third round with a bogey and continued to struggle Saturday. The 18-year-old who one month ago won the Women's PGA Championship shot a 4 over in the third round to fall to 7 over on the weekend.

Rival youngster Lydia Ko of New Zealand leads the tournament going into the final round. Other Canadians Maude-Aimee Leblanc and Alena Sharp shot 4 over and 3 over, respectively, to each end the round 1 over with a round remaining.

World No. 1 Lydia Ko birdied the 18th hole to cap a 2-under 70 that put her in the lead, bolstering her chance for her third major title in less than a year.

The 19-year-old Ko became the youngest woman to win a major last year at the Evian Championship and followed that up by winning the ANA Inspiration this spring. Now she's in contention for her first U.S. Open title after failing to make the top 10 in her first four appearances.

Ko has a one-shot lead over 2009 winner Eun Hee Ji and Sung Hyun Park. Brittany Lang and Amy Yang are two shots back at 5 under and Angela Stanford is in sixth place at 4 under at CordeValle.

Ko's week at the Open got off to a somewhat shaky start when she was tied for 52nd after a 73 in the first round in the difficult afternoon conditions.

But Ko got into contention with a 66 in the second round and then got right back to work on Saturday. She made a long downhill putt for birdie on No. 3 before losing a stroke with a bogey at No. 9. She made another birdie at No. 13 before her strong closing hole.

Ko's conservative approach pays off

Even though the 18th is reachable in two shots, Ko opted to take three and it paid off when her approach stopped about 9 feet from the hole. She calmly sank the putt to give her sole possession of the lead. She then threw her ball into the stands in celebration.

Ji has been consistent all week. She has broken par all three rounds with a 69 and 71 in the first two rounds followed by the 2-under performance on Saturday. She is looking for her first LPGA Tour win since winning the Open at Saucon Valley seven years ago.​

There are several other golfers lurking close enough to make a push on Sunday. Danielle Kang is at 3 under and fellow Americans Cristie Kerr, Stacy Lewis and Kris Tamulis are among seven golfers five shots back at 2 under.

"There's no doubt I have to shoot at least 4 to 6 under, I'd say tomorrow to have a chance," Kerr said. "It depends on the wind and the weather and the pins. Sometimes they like to set it up easier on Sunday and people get some low scores. I don't know what they're going to do, but I have to be prepared for anything. If the conditions are easier, I have to be prepared to go low."

The highlight of the day might have been Lee Lopez's ace on the 191-yard, par-3 12th hole. Lopez is at even par for the tournament.