Phil Mickelson returned to Royal Troon on Friday and retained his lead in the British Open despite battling rain and a host of challengers.Already soft, Troon became even more receptive with rain peppering Paul Molitor Jersey the Scotland course throughout the morning. The weather didn't bother Mickelson, who birdied three of his first eight holes en route to a 2-under 69.MORE: | "The conditions made it tough, especially when the wind and rain picked up. But I enjoy that challenge, it's fun," Mickelson said on the Golf Channel. "I think it's easier having been there. Winning the Open the first time was one of the greatest achievements in my career and it helps knowing I've done it before."Mickelson finished his halfway point at 10 under, one shot ahead of Sweden's Henrik Stenson. Stephen Vogt Jersey After a quiet, but solid opening round, Stenson came out on fire in Round 2, birdieing four of his first seven holes.MORE: Stenson shot a sterling 6-under 65 in Round 2. He was runner-up to Mickelson at the Open in 2013, and he is regarded as one of the best players without a major championship."I took my chances early and hit some good shots into greens," Stenson said on Golf Channel. "I had a tough bogey on 9, and it was tough conditions around the turn, but I was able to Matt Garza Jersey pick up a couple of birdies coming in. You just have to pick your spot and go for it" when the weather comes into play.Denmark's Soren Kjeldsen continued his impre sive major season with a 3-under 68 Friday to get to 7 under for the tournament. Kjeldsen burst onto the scene with a T-7 at the Masters, proving he has what it takes to stay in the running on golf's grandest stages.MORE: Despite struggling with the anchored putting ban that came into affect this season, Keegan Bradley vaulted up the leaderboard in Round 2. The fidgety American shot a 3-under Milwaukee Brewers Hoodie 68 to join Kjeldsen at 7 under.Reigning U.S. Open champion Dustin Johnson birdied holes 15 through 17 to get back into contention at 2 under. Johnson was down to 1 over for the tournament before his late run helped him shoot a 2-under 69 in Round 2. Though he's still eight shots back, Johnson has the firepower to make up ground in a hurry.Germany's Martin Kaymer climbed to 7 under early in his second round before he ran into disaster on the par-4 10th hole. He took a triple-bogey seven to fall back to 4 under. He finished his day at 3 under, seven shots back.MORE: Defending champion Zach Johnson shot a 1-under 70 on Friday to move to 5 under, setting himself up for a nice weekend charge. Johnson has two major championships on his resume already.With the weather getting worse by the second, Mickelson and Stenson could be sitting nicely at Ryan Braun Jersey day's end.