The second seed Lee Westwood was among the losers on a day of upsets in the second round of golf's $8.5 million WGC Accenture Match Play Championship in Arizona.
The third, fourth and fifth seeds, Jim Furyk, Martin Kaymer of Germany and Northern Ireland's Rory McIlroy were also eliminated, following the first round defeat of the top seed, Steve Stricker.
That's left the sixth-seed, Britain's Paul Casey, as the highest ranked player through to the final 16.
Westwood fell 2 and 1 against 31st-seed Nick Watney while the defending champion Geoff Ogilvy of Australia lost to Colombia's Camilo Villegas by the same margin.
Spain's Sergio Garcia and Japan's Ryo Ishikawa were among the few big names to advance while Retief Goosen knocked out fellow South African Ernie Els.