Tee times, groupings announced for 146th Open

SOUTHPORT, England -- Henrik Stenson will begin defense of his Open title on Thursday at 4:47 a.m. ET (9:47 a.m. local time) alongside two-time major champion Jordan Spieth and Players champion Si Woo Kim.

The Open starts at 6:35 a.m. local time with Mark O'Meara hitting the first tee shot. O'Meara won the Open at Royal Birkdale in 1998. He will be playing with American Ryan Moore and England's Chris Wood.

Ireland's Padraig Harrington, who won the last Open at Birkdale in 2008, begins play at 4:36 a.m. ET along with American Pat Perez and Belgium's Thomas Pieters.

Following Stenson's group will be 2010 Open champion Louis Oosthuizen, England's Justin Rose and American Justin Thomas.

Other notable groups include: Zach Johnson, Sergio Garcia and Jason Day (8:04 a.m. ET); Rickie Fowler, Adam Scott and Paul Casey (8:26 a.m. ET); Rory McIlroy, Dustin Johnson and Charl Schwartzel (9:48 a.m. ET); Jon Rahm, Patrick Reed and Lee Westwood (9:59 a.m. ET); and Phil Mickelson, Francesco Molinari and Marc Leishman (10:10 a.m. ET).

The last group tees off at 4:16 p.m. local time, 11:16 a.m. ET.

The Open does not use a two-tee start like the U.S. Open and PGA Championship. All players tee off the first hole. The groupings remain the same for the second round, with groups going off opposite of the first-round tee time.

The Open field is set at 156 players.