In a wild Day 2 at the 2013 Accenture Match Play Championship, numerous top seeds fell at Dove Mountain in Marana, Ariz.
Not only did Rory McIlroy and Tiger Woods fall, so did players such as Adam Scott, Lee Westwood, Jason Dufner and Keegan Bradley.
Here's a look at how it all went down on Thursday.
Shane Lowry (68) Defeats Rory McIlroy (1)
In an absolute stunner, world No. 68 Shane Lowry—who was coming off two straight missed cuts on the European Tour—defeated world No. 1 Rory McIlroy on Thursday.
The 25-year-old from Ireland simply was rolling on Day 2, posting five birdies and forcing a conceded hole. He did all of that damage from holes 6 through 15.
McIlroy birdied on hole No. 16, finding himself down one, but wasn't able overcome the damage already done in the final two holes. Lowry won, 1 up.
Charles Howell III (66) Defeats Tiger Woods (2)
Charles Howell III actually missed the cut at the Northern Trust Open before the Accenture Match Play Championship.
The 33-year-old stunned Tiger Woods on Thursday, posting four birdies—including some putts from long distance. His putting game was working beautifully and Tiger couldn't keep up.
The two competitors were all square through 14 holes, but Howell ultimately grabbed holes 15 and 16, nailing a 23-foot putt on the 16th hole to close out in style.
Woods wasn't able to make up any ground on hole No. 17 and Howell had himself a victory over the world No. 2 (2 up).
Rafael Cabrera Bello (60) Defeats Lee Westwood (8)
This was quite a surprise. While Lee Westwood has historically struggled in the Accenture Match Play Championship, nobody expected Rafael Cabrera-Bello to do what he did on Thursday.
Westwood was 3 up on the 28-year-old through nine holes, but the Spaniard came roaring back, posting four birdies on the final nine holes, including one at No. 18 that made it all square and sent it to hole No. 19. At hole No. 19, Cabrera-Bello birdied and defeated Westwood.
Tim Clark (61) Defeats Adam Scott (7)
Not only did Tim Clark defeat Adam Scott on Thursday, he didn't even have to play the final hole. He hadn't played in the Accenture Match Play Championship since 2010, but went 2 up on Scott through 17 holes, backed by four birdies and one conceded hole.
That marks the third straight year Scott has been bounced in the Round of 64. The 32-year-old Australian was coming off a 10th-place finish at the Northern Trust Open.
Richard Sterne (57) Defeats Jason Dufner (12)
Jason Dufner didn't advance past the Round of 64 last year, but you still expected the 35-year-old to defeat world No. 57 Richard Sterne on Thursday.
That didn't happen.
Sterne posted five birdies in the first 11 holes to start 4 up on Dufner. Dufner battled back—with birdies at holes 12, 14 and 16—but he couldn't birdie on the final two holes, falling just short.
Marcus Fraser (54) Defeats Keegan Bradley (15)
This was only Keegan Bradley's second career appearance in the Accenture Match Play Championship, but it was still surprising to see him go down to 34-year-old Marcus Fraser.
The world No. 54 knocked down five birdies en route to a 1 up victory, coming through in the clutch at hole No. 17 with a fantastic 26-foot putt.
Fredrik Jacobson (47) Defeats Ernie Els (22)
Fredrik Jacobson had only participated in the Accenture Match Play Championship three times in his career headed into this year's event, but that didn't stop him from disposing of Ernie Els on Day 2.
Els had four birdies on the day, but Jacobson posted five birdies, including the match-winner at hole No. 18. Els hasn't gotten past the Round of 32 since 2009.