Rory McIlroy took advantage of one of his favourite stretches of holes to produce a record-equalling performance and surge into contention in the Players Championship.
McIlroy began the day nine shots off the lead held by world number one Jason Day after struggling to an opening 72 on Thursday, when 82 players broke par in benign conditions at Sawgrass.
But it was a completely different story on Friday as the world number three covered the back nine in just 29 shots to equal the tournament record set just 24 hours earlier by fellow Irishman Shane Lowry.
McIlroy made a blistering start as he holed from 25 feet for birdie on the 10th and got up and down from a greenside bunker on the par-five 11th, before making it four birdies in a row on the 12th and 13th.
After a first par of the day on the 14th, the four-time major winner holed from six feet on the 15th for birdie and then from 50 feet across the green for eagle on the 16th, only to leave another long-range putt just inches short on the famous par-three 17th.
The 27-year-old, who has finished eighth, sixth and eighth in the last three years, had to settle for another par on the 18th but the brilliant run of scoring meant he has now played the back nine in 44 under par since 2013, compared to 13 over par for the front nine.
At seven under par McIlroy had also moved to within two shots of Day, who was among the later starters, and Sweden's Jonas Blixt, who had four holes of his second round to play.