Bubba Watson squandered an early five-stroke advantage and was caught by 20-year-old Jordan Spieth as the youngster tied him for the lead at the end of a pressure-packed third round of the Masters.
Spieth, playing with patience and discipline belying his years, posted a solid two-under-par 70 to join Watson on five-under 211 on a warm, sunny day at Augusta National that baked the famed greens to lightning speeds.
"Patience," Spieth said about the key to his round. "We could tell early on the greens were ridiculous. You had to put the ball on the right spots and not let your focus stray for one moment."
Spieth, who began the day four behind overnight leader Watson, put himself in position to make Masters history on Sunday as victory would make him Augusta's youngest champion, putting him ahead of Tiger Woods who was 21 when he triumphed in 1997.
Watson, the 2012 champion, needed to curl in a four-foot par-saving putt at the last to retain a share of the lead on a day when he struggled on the heavily contoured greens.
"It was the firmest I've seen it in years out here," said Watson who only missed one fairway but needed 33 putts.
"I had a couple of three-putts. If you two-putt those you're right there and you've got a two-shot lead. All in all, a good day. If somebody told me on Monday I'd have a 74 and still be tied for the lead I'd have taken it all day long."
One stroke back were Matt Kuchar, who used some brilliant chipping to register a 68, and Masters first-timer Jonas Blixt of Sweden (71).