SOUTHPORT, England -- With both the world No. 3 and the reigning U.S. Open champion as part of a three-way tie at the top of the leaderboard, plus a host of high-caliber players right behind them, Royal Birkdale is set for an entertaining weekend of golf.
But who are the players who need to keep their wits about them on Friday just to make it to Saturday? Which of the leading lights have most to fear when the cut mark falls after Round 2?
Our writers make their picks for who to watch out for on Friday.
Dustin Johnson
One birdie for his entire round on a day when there were plenty of birdies to be had for a bomber. DJ did have only 26 putts for the round but that shows his iron play left much to be desired. He's 1-over and in a tie for 58th right now, so he has given himself very little wiggle room Friday. In order for the world No. 1 to make the weekend, he's going to have to shoot even par or better.
-- Michael Collins
At 1 over par, he's on the cutline now, so perhaps there is no reason for alarm. But the troubling thing for Johnson is his stunning lack of birdies. He made just one in the first round. That follows making just four during two rounds at the U.S. Open and only two during two rounds at the Memorial, missing the cut at both.
-- Bob Harig
Phil Mickelson
There's little doubt Lefty is still smarting from last year's defeat at The Open, when he posted 17-under, beat 154 players and still lost by three to Henrik Stenson. Following an opening round during which he failed to make a single birdie, Mickelson will need to be his usual aggressive self if he's going to make the cut and get into contention over the weekend. He has done it before, of course, but this time might be a little more daunting.
-- Jason Sobel
Rory McIlroy
Midway through his round on Thursday, it looked like Rors was headed for yet another missed cut at a major. He was missing greens and missing putts in a way that made you want to cringe. An impressive back-nine birdie run gave him life, but I'm still not convinced he has learned to control his ball flight in bad weather. I'd love to see him in contention -- majors have a different kind of energy when he's in the mix -- but I remain skeptical after an injury and equipment change that he's as close as he says he is to playing great again.
-- Kevin Van Valkenburg
Sergio Garcia
He has played every Open Championship of the 21st century and missed the weekend just twice, but he'll need to demonstrate all of his linksland wiles to fend off the Friday cut. Closing out his first round with back-to-back birdies offers hope but he'll need to dial in his tee shots because he found the fairways just three times from 14 tries on Thursday.
-- Matt Cooper
Louis Oosthuizen
The 2010 champion at St. Andrews -- who lost in a playoff to Zach Johnson at the same venue two years ago -- looked anything but a contender on Thursday. Going out early in the day's slightly less favorable conditions, the one bright spot of a birdie on 11 was eclipsed by two double-bogeys to go with two bogeys on the way out, and another two on the way back. His lowest Open Championship score is a 65 and he might need to be better than that unless the weather plays havoc with the rest of the field on Friday.
-- Leo Spall