Peter Hanson leads Phil Mickelson by a stroke at nine under with a round to play at the US Masters as the Australian challenge faltered at Augusta and Tiger Woods temper got the best of him.
Hanson shot the lowest round of the tournament, a seven-under 65, to storm to the top of the leaderboard although Mickelson birdied the last hole to close the lead to a stroke.
South Africa's Louis Oosthuizen carded a three-under 69 to take outright third and set up what will be an intriguing final day at Augusta.
Oosthuizen had shared second with Mickleson but dropped a stroke at the last to sit two behind Hanson.
Mickelson was on fire with the putter as he blitzed the back nine in 30 after his 20-foot birdie putt at the last, the American finishing the day with a six-under 66.
Americans Bubba Watson and Matt Kuchar both birdied the last to move to six and five under respectively.
Four players including Ireland's Padraig Harrington, Hunter Mahan, Henrik Stenson and Lee Westwood are outside chances at five shots off the pace on four under.
Australian Geoff Ogilvy finished his third round with a one-under 71 to be one-over par.
Countrymen Adam Scott and Aaron Baddeley were a shot and two shots further back respectively.
Baddeley remained in contention after round two at two-under but endured a torrid third round, as he dropped five shots, including two double-bogeys on the 14th and 18th, to go around in 77.
A year a ago the trio of Scott, Ogilvy and Jason Day, who withdrew from this year's tournament with a leg injury, all secured top-six finishes at the Masters.
US Open winner Rory McIlroy had a horror round that saw him fall well out of contention, with two double-bogeys and four bogeys in his five-over round.
The Northern Irishman fell from four under with a double bogey at the par-four first hole and was six over for the round after nine holes.
Four-time champion Tiger Woods endured a frustrating afternoon and may be sanctioned by the PGA after a temper tantrum saw him kick away his nine iron.
Woods' hopes of a fifth green jacket would appear to be over after his even-par 72 kept him on three-over-par, nine strokes behind leader Hanson.