AUSTIN (REUTERS) - Rory McIlroy and Jordan Spieth were among the early losers in Wednesday's opening day of the WGC-Dell Match Play as the two former world No. 1 players suffered stunning upsets.
McIlroy, who reached last year's semi-final, fell 2&1 to Dane Soren Kjeldsen while Japan's Hideto Tanihara, making his first appearance at the tournament, beat Spieth 4&2 at the Austin Country Club.
Kjeldsen, who does not have a top-25 finish in any of his seven starts this year, stuck his tee shot at the par-three 17th to three feet and made the birdie putt to close out world No. 2 McIlroy, who had held a 1-up lead with five holes to play.
Northern Irishman McIlroy, who replaced Jason Day as world No. 2 this week, will play Gary Woodland on Thursday and Argentine Emiliano Grillo on Friday. Woodland beat Grillo 3&2.
Twice Major champion Spieth never led against Tanihara, who has 13 career titles overseas. The American played his last nine holes in three over and hit only one green to end his chances.
It marked the first time in four years that Spieth had lost his opening match.
Next up for the Texan is a clash with Japan's Yuta Ikeda on Thursday and Ryan Moore on Friday. Moore halved his match with Ikeda.
Japan's Hideki Matsuyama and US Ryder Cup Captain Jim Furyk halved, while Brooks Koepka was lights out with the putter in a 6&5 trouncing of fellow American Kevin Kisner.
World No. 1 Dustin Johnson won the first three holes and was five up after nine holes and steamrolled Webb Simpson 5&3.
Day, last year's winner, walked off the course after six holes, revealing to reporters that he was leaving to be with his mother, who is having lung cancer surgery on Friday.
"Hard to comprehend being on the golf course right now with what she's going through," said a tearful Day. "Family is first."
The event is comprised of 16 four-player groups who play round-robin matches from Wednesday through Friday with the winners of each group advancing to a single-elimination bracket at the weekend.
Players receive one point for a win and a half-point for a halved match that ends in a tie.