TROON - Phil Mickelson followed his stunning opening round with a solid 69 in miserable weather conditions at Royal Troon on Friday to lead the British Open at 10 under par. The American had led overnight after equalling the lowest ever round in a major championship when he shot 63 in glorious conditions on Thursday afternoon.

He was back out early on Friday morning and this time had to deal with the wind and, above all, rain that left the players and the course on Scotland's west coast sodden. But he still thrived, with three bogeys on the front nine, including at the short eighth, the Postage Stamp, when he almost holed his tee shot.

He also birdied the short 14th, although there was a dropped shot -- his first of the week -- at the 12th and another bogey at 15 that brought him back a little closer to the pack.

"I thought it was a good round to back up the low round yesterday. I made one or two bad swings that led to bogeys but for the most part I kept the ball in play and played stress-free golf," said the American, who won the Open at Muirfield in 2013 and admitted he enjoyed the unpleasant conditions that can constitute a Scottish summer.

"I was actually more worried about yesterday's round than I was about these coming rounds because I feel very comfortable in the conditions to be able to shoot a number, shoot a good score. I was worried about guys going low on the beautiful day and then not keeping pace, so yesterday's round was a big round for me to ultimately set the pace, and not lose too much ground, because I felt like I'd be best prepared for days like today."

As it is Mickelson leads in the clubhouse by one shot from Henrik Stenson after the Swede produced a stunning second-round 65 to go to nine-under overall. The effort, which equalled his lowest ever round at a major, featured seven birdies and just one bogey and gave him every chance of finally winning at a major this weekend.

Also looking good in the clubhouse was his fellow Scandinavian Soren Kjeldsen of Denmark, who scored a three-under-par 68 to move to seven-under heading into the weekend. Reigning champion Zach Johnson is still in the running to become the first player to win the Claret Jug in successive years since Padraig Harrington in 2007 and 2008.

He had a one-over 70 to go to five-under overall, although for the second day running Johnson bogeyed the last, one of four dropped shots in his round. The favourite coming into the weekend, US Open champion Dustin Johnson, had an unremarkable opening round of 71 but he produced an eventful 69 on Friday to go to two-under.

The American had six birdies, including three in a row from the 15th, but marred his card with double-bogey sixes at the seventh and the treacherous 11th. "I felt like I swung it really well all day. Hit a lot of great shots, so I'm looking forward to this weekend," Johnson said.

South Africa's Charl Schwartzel, the former Masters champion, shot a stellar five-under-par 66 featuring seven birdies to go to four-under overall heading into the weekend. Rory McIlroy, who was two-under overnight, Jordan Spieth and world number one Jason Day were among those with afternoon tee-times on Friday. They were all hoping that the filthy weather, with rain and low cloud obscuring the mountainous Isle of Arran out in the Firth of Clyde, would clear up. It was already too late for a number of players who will miss the cut, including Graeme McDowell, Ernie Els and Todd Hamilton, who won the last Open at Troon in 2004.

Then there was Ben Curtis, the 2003 champion who was 18-over after an awful round of 12-over 83 -- that included an inexplicable 10 at the par-four third and seven bogeys, although there was a birdie at 18.