(Reuters) - American Daniel Berger moved within sight of his second victory in two months when he opened a three-shot lead after the third round of the Travelers Championship in Cromwell, Connecticut on Saturday.

Berger, last season's rookie of the year on the PGA Tour, picked up nine birdies to surge clear with an eight-under-par 62 at the TPC River Highlands.

The 23-year-old posted a 15-under 195 total, three ahead of Scotland's Russell Knox (64), South African Tyrone Van Aswegen (65) and American Russell Henley (65).

Low scores were plentiful on a day when Ernie Els made his first ace on the PGA Tour since 2004, using a seven-iron from 171 yards at the 16th.

"I made a bunch of putts and that's what it takes to shoot a low number out here," world number 40 Berger told PGATour.com.

"It didn't really feel like I was that many under par until I looked at my scorecard walking down the 18th hole but sometimes it happens like that.

"I'm striking it really well, driving it well and that's going to be a big key tomorrow."

Berger, who won the St Jude Classic in June, was not the only player to go low.


Knox adopted a simple attitude and it paid off with birdies at the first three holes.

"Aim at the pin, you might hit it there," said the Scottish winner of the WGC-HSBC Champions event in Shanghai in November.

"I played beautifully. I had loads of chances, obviously made some, which was great, missed a couple."

Van Aswegen hit back well after dropping a stroke at the first.

"I started off real nervous," he said. "I wasn't feeling too good after that bogey but settled down, found a good rhythm and made some birdies coming in. Hopefully tomorrow I can find a rhythm a little earlier."

Fellow South African Els ended the day tied for 60th but the hole-in-one was a nice consolation for the four-times major winner.

"You hit a lot of good shots but rarely do they go in," he said. "It was a real thrill.

"All of us, from the 24-handicapper to the pro, it's a great feeling, a feeling of elation.

"I think everybody feels the same way. When the ball goes in we're all kind of surprised."

(Reporting by Andrew Both; Editing by Tony Jimenez)