Tommy Fleetwood held a share of the lead at the halfway stage of the WGC-Bridgestone Invitational after firing seven birdies in a sparkling second-round 63.
Race to Dubai champion Fleetwood began the day four strokes behind overnight leader and fellow Englishman Ian Poulter after posting a four-under-par 66 at Firestone Country Club on Thursday.
But he followed up three birdies on his front nine with four more after the turn on Friday to join fellow early starters Poulter and World Number Three Justin Thomas at the top of the leaderboard on 11 under par.
Poulter had led by three shots during his second round after making three birdies in his first 11 holes but he mixed two birdies with two bogeys in his next seven to follow up Thursday's 62 with a 67.
Thomas, meanwhile, finished with a flourish as he notched five birdies on his back nine on the way to a 64.
Later starters Kyle Stanley and Jason Day were their nearest challengers on nine under, with Northern Irishman Rory McIlroy and Si Woo Kim another stroke further back in a tie for sixth.
Stanley caught up with the co-leaders at one stage in his second round after carding four birdies in his first 11 holes but a four-putt double bogey at the short 12th saw him slip back as the South Course bared its teeth in the afternoon.
Fleetwood, starting his second round at the tenth tee, rolled in his first birdie of the day at the 11th before making another at the 13th.
The 27 year old then took advantage of the par-five 16th before safely parring the 17th and 18th to reach the turn in 32 shots.
And World Number 11 Fleetwood made the perfect start to his back nine, converting his 25-foot birdie putt at the first before following that up with another gain at the long second.
After sending his tee-shot to within two feet of the fifth hole to set up another birdie, Fleetwood holed his long putt at the seventh to join Poulter on 11 under.
And he came agonisingly close to finishing his round with another gain at the ninth, only for his 20-foot putt to slide just by.
Fleetwood, who produced his lowest-ever score at a World Golf Championships event on Friday, was pleased with his day's work.
He said: "No fives on the card is always something nice to look at.
"I played well. I got out of position a couple of times but when I did, I kind of got away with the tee-shot on the 14th and made a really good four.
"Overall I drove it well. My irons, I just tended to hit exactly where we were picking the spots and I holed a few putts.
"You've got days like that where it's going well and you've just got to make the most of them."
Poulter vowed to continue playing aggressively after making a brilliant start to the tournament.
He said: "It's never going to be easy just to go out there and feel like, 'Hey, we're going to go and do another 62'.
"But I'm playing well, I feel aggressive. I feel like the greens, with the way they are, you can be super aggressive, and that's what I need to do.
"I need to keep reminding myself that if I play aggressively, it kind of brings out some of the good golf in me and I need to continue that."
Thomas was happy with his second-round display. He said: "I played well overall.
"I putted a lot better today - or I made more putts. I gave myself quite a few opportunities but not as many as I did yesterday.
"But I was just able to capitalise on more of them today."
China's Haotong Li, who celebrated his 23rd birthday with an eagle at the second, was in a tie for eighth on seven under.
