TROON, Scotland -- Zach Johnson begins defense of his Open title on Thursday at 9:15 a.m. ET at Royal Troon along with Adam Scott and Henrik Stenson on the opening day of the 145th playing of the championship.
U.S. Open champion Dustin Johnson is in the group prior at 9:04 a.m. along with Martin Kaymer and Russell Knox.
Each of the 156 competitors in the field begins off the first tee. The tournament will start with Scotland's Colin Montgomerie, 53, at 1:35 a.m. ET hitting the opening shot in a group with Marc Leishman -- who lost in a playoff to Johnson last year -- and Luke Donald.
Other notable groups include Jordan Spieth, Justin Rose and Shane Lowry (4:03 a.m.); Masters champion Danny Willett, Rickie Fowler and Jason Day (4:25 a.m.); Rory McIlroy, Hideki Matsuyama and Bubba Watson (4:36 a.m.); Graeme McDowell, Matt Kuchar and Andrew Johnston (8:15. a.m.); Phil Mickelson, Lee Westwood and Ernie Els (8:26 a.m.)
The last group tees off at 11:16 a.m.