Rory McIlroy to face Jason Day in Match Play semi-final

Defending champion Rory McIlroy remains on course to retain his WGC-Dell Match Play title after setting up a mouthwatering semi-final with new world number one Jason Day.

McIlroy, who has yet to successfully defend a tournament in his professional career, edged past British Open champion Zach Johnson on Saturday morning before beating American Chris Kirk 4&3 in the quarter-finals at Austin Country Club.

And with Jordan Spieth losing in the last 16 to Louis Oosthuizen, Day's quarter-final win over Brooks Koepka was enough to see him replace Spieth at the top of the world rankings when they are updated on Monday.

“It’s been a great day,” McIlroy told Sky Sports. “This morning against Zach we probably both did not have our best stuff. It was a bit of a scrappy game but I felt like I played good golf when it mattered and birdied the last to beat him one up when he holed a 20-footer on top of me to make it interesting.

“I battled away in the morning to session to get a win and this afternoon I played much better. I started with a nice birdie on the first and there were a couple of mistakes at the end of the front nine, but I think I was four under for the six holes played on the back nine and with the wind up, that will always get the job done.”

The win extended McIlroy’s unbeaten streak in the event to 12 matches and just one shy of the record held by former world number one Tiger Woods, who won it in 2003 and 2004 under the previous straight knockout format, before losing in the second round to Nick O’Hern in 2005.

McIlroy was two up on Kirk after four holes before driving out of bounds on the fifth and then three-putting the ninth, but edged back in front with a birdie on the 10th.

Another birdie on the par-five 12th doubled McIlroy’s lead and when Kirk’s second shot to the 13th span into the water surrounding the green, the writing was on the wall for the world number 56, who had beaten compatriot Bill Haas 2&1 in the last 16.

Day, who had seen off Brandt Snedeker 3&2 in the last 16, told Sky Sports: "It's great to get back to world number one but I enjoy the journey of getting there and climbing the mountain through the process of things and winning golf tournaments.

“It’s going to be a difficult match (against McIlroy). Rory hits it so good he is never really out of a hole because of how electric he can be so it’s going to be a very stressful, enjoyable match tomorrow.”

The other semi-final sees Oosthuizen take on Spain's Rafael Cabrera-Bello after they enjoyed quarter-final wins over Dustin Johnson and Ryan Moore respectively.

Former British Open champion Oosthuizen followed his victory over Spieth by beating eighth seed Johnson 2&1, while 52nd seed Cabrera-Bello defeated Moore by the same score.

Cabrera-Bello had earlier been the first player into the quarter-finals by defeating Korea’s Byeong Hun An, a win which also sealed a Masters debut next month.

An inspired Cabrera-Bello was about to move five up with six to play when An signalled on the 12th green that a neck injury meant he was unable to continue, thereby ensuring the Spaniard of winning enough world ranking points to move inside the top 50 in time for the final qualifying deadline for the year’s first major championship on Monday.

“Obviously I’m very pleased,” Cabrera-Bello told Sky Sports. “It was the only Major I had not played before and it’s the one that really got me dreaming about being a professional thanks to Olly (Jose Maria Olazabal) winning there twice.

“I’m still concentrating on this week, there is a lot of golf to be played, but I am really, really excited about the Masters.”