Jordan Spieth shoots sizzling 61 to take two-shot lead at John Deere Classic

Jordan Spieth warmed up for an attempt at the third leg of a possible golfing Grand Slam at the British Open next week by charging into the lead with a stunning 10-under 61 in the third round at the John Deere Classic on Saturday.

The Masters and US Open champion used a mixture of precision and luck to finish birdie, eagle, birdie at TPC Deere Run.

He holed out with a sand wedge from 107 yards at the par-five 17th, before running in a 15-foot birdie at the last for a 10-under-par 61, his best round on the PGA Tour.

"I just seem to get some lucky breaks here at the John Deere," Spieth told Golf Channel after posting a 17-under 196 total, two strokes better than New Zealand's Danny Lee, who shot 62.

It has been a stunning form turnaround by the 21-year-old American, who was in danger of missing the cut until he put together a string of birdies in the middle of the second round.

Some questioned whether Spieth should play in the US the week before the British Open at St Andrews, where he will have a chance to become the first player since Ben Hogan in 1953 to win the first three Majors of the year.

But he had no hesitation returning to the course where he won his first PGA Tour title two years ago.

“That turning point mid-round yesterday where I had a really good stretch to get inside the cut line is what really gave me a lot of confidence,” he said.

“The hole looked a little bigger from there on in. In order to shoot a really low round you obviously have to have some putts go in from mid-range.”

Spieth hit a poor drive at the 17th but threaded a nice recovery shot between the trees.

He was clearly disgusted with his third shot but was then surprised when his ball landed about eight feet beyond the hole, put on the brakes and was sucked back into the hole.

“It was certainly a couple of grooves low (on the clubface) but that seems to be something that works out for me at this tournament. Just thin it a little bit and somehow it goes in.”

Lost in the drama was Lee, whose 10-birdie 62 lifted him into contention to win for a second successive week, after his breakthrough victory at the Greenbrier Classic last Sunday.

“I feel very confident about tomorrow,” Lee said. “Jordan just played magnificent today. I think it’s going to be a fun day for us tomorrow.”