Rory McIlroy has sealed his place in the last 16 of the World Golf Championship in San Francisco following his victory over Billy Horschel.
The world number one needed to beat the American to progress from Group 1 courtesy of his narrow win, which took an additional two holes of the course to secure.
McIlroy will play Japan's Hideki Matsuyama in the next round of the competition following his 5&4 triumph over Kevin Na to complete a clean sweep of Group 16.
Lee Westwood overcame Jordan Spieth in Group 2 to earn his place in the last 16 of the tournament with a 2up victory over The Masters champion, and will face off against fellow Englishman Danny Willett.
Justin Rose's win over Ryan Palmer was not enough to see him through to the next round as Australian Marc Leishman earned the berth from Group 6, and he will play Gary Woodland.
Paul Casey set up an encounter with South African Charl Schwartzel following his victory over Francesco Molinari, while Jim Furyk will play compatriot JB Holmes in the next round.
Graeme McDowell's miserable competition ended with a 5&4 defeat to Rickie Fowler to leave the American with a showdown against Louis Oosthuizen.
