World number one Dustin Johnson remained on course to create history as he reached the final of the WGC-Dell Technologies Match Play on Sunday.
Johnson, who is looking to become the first player to have won all four World Golf Championship events, beat Japan's Hideto Tanihara by one hole to set up a mouthwatering showdown with Spain's Jon Rahm at Austin Country Club.
Rahm beat American Bill Haas 3&2 in their semi-final and will become the youngest ever winner of a WGC event if he can overcome Johnson in the 18-hole final.
The 22-year-old, who was the world's top-ranked amateur while studying at Arizona State University, is currently 25th in the world after winning his first PGA Tour title in the Farmers Insurance Open at Torrey Pines in January.
And he could rise as high as 10th in the standings with victory in his just his second World Golf Championships event, having finished tied third behind Johnson in Mexico earlier this month.
Johnson and Tiger Woods are the only players with four or more WGC titles and although Woods won an incredible 18, the former world number one failed to collect the HSBC Champions trophy in his only two appearances.
There was never more than one hole between Rahm and Haas until the former followed a birdie on the 13th with another on the 15th, before sealing victory by getting up and down from a greenside bunker on the par-five 16th.
Johnson had appeared in command against Tanihara when he reduced the par-five sixth to a drive and an eight iron to set up an eagle, before moving further ahead with a birdie on the next.
Tanihara, who defeated two-time major winner Jordan Spieth in his first group match, reduced his deficit to a single hole before losing the 12th after three-putting it for par, but birdied the next two holes to get back to all square.
Seeking a third win in succession and to become the third player after Rory McIlroy (2015) and Woods (three times) to win this event as top seed, Johnson had not been taken to the 17th hole all week.
But the US Open champion produced a superb tee shot to set up a birdie from six feet to regain the lead, before scrambling a par on the 18th after Tanihara had missed from 12 feet to force extra holes.