An improbable round of 67 has given 52-year-old Fred Couples a share of the lead after day two of the Masters in Augusta.
The 1992 winner, who started the day on level par, hit seven birdies to put him on five-under alongside fellow American Jason Dufner.
Overnight leader Lee Westwood dropped one shot as he ended the day on four-under with Rory McIlroy, Sergio Garcia, Louis Oosthuizen and Bubba Watson.
American Phil Mickelson was one of the biggest movers as he finished on two-under with seven others after starting the day on two-over.
Elsewhere, defending champion Charl Schwartzel endured a difficult time on the course as the South African finished on three-over with Tiger Woods, who played another forgettable round. Luke Donald hit two bogeys and a double-bogey to put him on four-over.
Notable players who missed the five-over cut were England's Paul Casey, Spain's Jose Maria Olazabal (both 7+) and Ireland's Darren Clarke (10+).
