Ian Poulter and Luke Donald have failed to progress from the first round of the WGC World Match Play at Dove Mountain in Arizona.
Former world number one Donald crashed out 5&4 to Italian Matteo Manassero, while 2010 winner Poulter lost 2&1 to Rickie Fowler of the USA.
Fellow Briton Rory McIlroy made it through the the last 32 of the competition by seeing off Boo Weekley 3&2, but there was no such joy for Lee Westwood, who was beaten 5&3 by Harris English.
Ex-US Open champion Graeme McDowell came back from four down after seven to defeat Gary Woodland at the first extra hole, while Sergio Garcia got the better of Australian Marc Leishman over 22 holes.
American Dustin Johnson, joint eighth in the world with Garcia, was beaten 4&3 by Peter Hanson of Sweden.
Last-32 matches:
Henrik Stenson vs. Louis Oosthuizen
Brandt Snedeker vs. Webb Simpson
Jason Day vs. Billy Horschel
George Coetzee vs. Patrick Reed
Rory McIlroy vs. Harris English
Charl Schwartzel vs. Jim Furyk
Sergio Garcia vs. Bill Haas
Rickie Fowler vs. Jimmy Walker
Justin Rose vs. Ernie Els
Jason Dufner vs. Matteo Manassero
Matt Kuchar vs. Ryan Moore
Jordan Spiethl vs. Thomas Bjorn
Richard Sterne vs. Hunter Mahan
Graeme McDowell vs. Hideki Matsuyama
Peter Hanson vs. Victor Dubuisson
Bubba Watson vs. Jonas Blixt
Mark Langshaw
