Jason Day set up a mouth-watering semi-final against Rory McIlroy and ensured he will regain the world No.1 ranking with two wins at the world matchplay in Texas today.
Day beat Brandt Snedeker in the round-of-16 then backed up to beat Brooks Koepka of the United States 3 and 2 in a quarter-final to surge into the semi-final against McIlroy tomorrow.
The battle of the world No. 2 and No. 3 is a match-up of the last two winners of this World Golf Championship event.
Day held the No. 1 ranking for four weeks last year but was overtaken by Jordan Spieth late in the year.
But Spieth's defeat today by South Africa's Louis Oosthuizen ensures that the Australian will be back to the top of the pile when the rankings are released tomorrow, regardless of what happens in the semi-final. Under the rolling rankings, Day only needed to go farther in the Dell Matchplay than Spieth this week to overtake him.
Day, the 2014 matchplay winner, won the first hole against Snedeker and was never overtaken in the morning match. His third birdie of the day, at the ninth with a five-metre putt, put him two-up at the turn before the American lost the next hole with a bogey.
Day conceded the 13th after finding the water with his tee shot, then bogeyed the 15th. But he closed out the match with an eagle from just more than two metres at the 16th.
In the afternoon the Australian was in control throughout against long-hitting Koepka, taking the lead with a birdie at the par-fourth eighth and holding on for the rest of the way. Needing a birdie to extend the match at the par-five 16th, Koepka could not make his putt from seven metres, and Day rolled in a par putt from just less than two metres to win.
Afterward, he said it was the way he had reached the top that most pleased him. "It's not so much the No. 1 rank that gets me excited about, it's moreso the journey and the process it's taken,'' he said. "It takes a long time. For me it's that delayed grati aI'm really thankful for and really happy for. Because I have busting my butt and doing the right things and to be able to get back to No. 1 in the world is fantastic. The next step is try to get into tomorrow's round. I know I've got a really tough one tomorrow, I'm just looking forward to it.''
Looking forward to the McIlroy match, he expressed excitement. "I think we'll have a lot of fun,'' said Day. "I just hope the weather's good for us and it can heat up as quickly as possible. My back is a little shot right now. I'm going to have a lot of fun tomorrow no matter what happens.''
Spieth's defeat was a surprise. "I had great ball control the last three days,'' said the American. "Played very, very solid rounds. I got to the range this morning and I was hitting slices with my irons, which is bizarre. I never really get that. I tried to fix it on the range, didn't know what was up."
Spain's Rafael Cabrera Bello is into the other semi-final and will play Louis Oosthuizen of South Africa.
For the second consecutive day, the players will have 36 holes to play.