Top overall seed and defending champion Luke Accenture Match Play Championship.
Donald drew no ordinary No. 64 seed.
"Obviously playing against Luke, I needed to be on," Els said in a televised interview. "I knew had to play really well and I did. I kept it in play and made some big putts in the end."
Donald never trailed en route to victory last year and he never reached the 18th green. He didn't get there on Wednesday, either, but that was due to the play of his Hall of Fame opponent.
Donald never led in the match and Els built a 2-up lead at the turn. Donald fought gamely, but never won another hole. Els took the 11th, 12th and 14th holes to knock off the No. 1 player in the Bobby Jones bracket.
Tiger Woods, a three-time champion, holed a gutsy 12-foot par putt to beat Gonzalo-Fernandez Castano. Woods, seeded No. 5 in the Sam Snead bracket, didn't have his best game, but hung tough and did better than last year when he was eliminated in the first round.
"We both made our share of mistakes; there's no doubt about that," said Woods. "But somehow I was able to move on."
Woods fell 2-down right out of the gate, but built a 1-up lead with wins at five, seven and eight. Woods stumbled badly with losses at 10 and 11, then made a tough par save just to halve the 12th and stay 1-down.
Woods squared the match with a birdie at 15 and Fernandez-Castano let one get away at 16. He had six feet to halve the hole, but missed to give Woods a 1-up lead.
After pars at 17, Woods' second flew into the back bunker at the last. He had a tough shot from the trap with little green to work with and did well to get it 12 feet past the flag.
Fernandez-Castano had a decent look at birdie, but missed and was conceded par. Woods needed to make his putt to avoid extra holes and did just that.
The bottom portion of that bracket featured all upsets. Matteo Manassero, No. 15, eliminated the second seed, Webb Simpson, 3 & 2. Martin Laird knocked off Alvaro Quiros, 1-up, while Ryo Ishikawa won the 18th to upend last week's Northern Trust Open winner and third seed, Bill Haas, 1-up. Paul Lawrie, the 11th seed, beat Justin Rose, 1-up.
The rest of that bracket almost totally went in form with higher seeds Steve Stricker, Louis Oosthuizen, Matt Kuchar, Bubba Watson and Hunter Mahan winning. The only major upset was 14th-seeded Y.E. Yang knocking off No. 3 Graeme McDowell, 2 & 1.
"I felt like I played pretty good," McIlroy said in his televised interview. "Thankfully I'm through to the second round."
The No. 2 seed in the Player bracket, Jason Day, won the last three holes in regulation, then the first playoff hole to beat Rafael Cabrera-Bello. Day's opponent Thursday will be John Senden, the 10th seed, who beat Simon Dyson, 4 & 3.
NOTES: It was the third time the No. 1 overall seed lost in the first round...There were 15 upsets in the first round, the second-most in tournament history...The second round is on tap for Thursday, and the third round will be played Friday. The quarterfinals are Saturday, then the semifinals Sunday morning, followed by the final and consolation match in the afternoon.