Dustin Johnson was on course to make it back-to-back World Golf Championships victories as he took a commanding four up lead after nine holes of the WGC - Dell Technologies Match Play final against Jon Rahm.
Johnson and Rahm finished first and third at the WGC - Mexico Championship earlier in the month and were the form players at Austin Country Club, both boasting 100 per cent records coming into Sunday's final.
The World Number One's form was particularly remarkable as he had never trailed having played 103 holes, and only lost 19 of those.
He played the front nine in one under par in contrast to Rahm's three over and was set to become just the second player ever after Tiger Woods to win consecutive WGC titles.
In the consolation match, Hideto Tanihara was all square after 11 holes against Bill Haas with the help of a hole-in-one on the seventh.
Johnson failed to birdie the opener for the first time in the week as holes and one and two were halved in pars but a ragged tee-shot on the third led to a Rahm bogey and the American had the advantage.
A little frustration looked to be creeping into Rahm's body language and when he three-putted the next to send Johnson two up, it was clear he needed something positive to happen.
It looked like it had when he hit the pin on the fifth with his second shot to leave a short putt for birdie but after Johnson had got down in three, he missed from four feet to go three down.
The Spaniard recovered well from a poor second shot to save par on the sixth but Johnson was relentless and a textbook two-putt birdie on the par five gave him a four-hole advantage.
The rot was stopped on the seventh as Rahm recovered from sending a long putt off the green by making the next for par but a bogey on the eighth sent him five down before Johnson bogeyed the ninth.
In the consolation match, Tanihara won the second with Haas hitting back on the fifth before the Japanese made just the fourth hole-in-one in the history of the WGC - Match Play.
He hit an eight iron from 207 yards that took a big bounce, three hops and rolled into the hole for the tenth ace of the European Tour season.
He moved two up on the ninth but Haas hit back on the tenth and 11th.