A back nine birdie blitz has given talented Newcastle golfer James Nitties a one-stroke lead after the second round of the NSW Open golf tournament at Stonecutters Ridge in western Sydney.

Nitties fired a six-under 66 to lead at 13-under the card from 19-year-old amateur Justin Warren.

Nitties, fresh from retaining his card on the US-based Web.com tour, birdied all three par-fives on the back nine (10, 15 and 18) as well as the difficult par-four 12th and the par-four 14th.

His improved form could be a direct result of a change in putting technique.

A competent-yet-streaky putter for most of his career, Nitties made the choice to change his grip from conventional to the claw – and it’s working wonders thus far.

“I changed my putting grip from regular to clawing it this week and that’s a pretty drastic change,” Nitties said.

“But I hadn’t been putting well over four rounds for a long time.

“I’ve missed a couple of short ones, but I have made a lot of ten-footers this week, so that’s a positive.”

He also chipped in on the par-four ninth for a birdie, which got his round going again after a double-bogey on the seventh.

Nitties will play with Warren in the final group and is looking forward to the excitement the 19-year-old will bring.

Warren, who for the second straight day held the clubhouse lead only to end up one-stroke back, is happy with his form.

And like Nitties he has been hot on the greens.

“I feel like I’m playing really well,” Warren said.

“I didn’t play quite as well as yesterday, didn’t hit as many good shots, but I’ve been rolling some good distance putts in, which has saved me so hopefully I can keep doing that on the weekend.”

New Zealander Josh Geary is two strokes back from Warren at 10-under, while veteran Matthew Millar and Nathan Green are a further shot back and tied for fourth place.

Victoria’s Anthony Brown shot the low-round of the day with a seven-under 65, which included an eagle on the par-four seventh hole.