Rory McIlroy remains on course to complete a hat-trick of victories after taking a one-shot lead at the halfway stage of the US PGA Championship at Valhalla.
The 25-year-old from Northern Ireland, who arrived in Louisville after adding the WGC-Bridgestone Invitational title to his Open triumph, followed up his first-round 66 with a four-under 67 to move to nine under 133.
McIlroy made a slow start on the back nine in torrential rain and dropped a shot at the 12th hole.
The world No 1 got back on track with birdies at the 13th and 15th and missed from six feet for another on the 16th.
The highlight of his round came at the 18th when he holed from 30 feet for an eagle and he could have had another eagle on the seventh but missed from eight feet after a stunning five-wood approach.
However, a birdie there took him into the lead on eight under and he completed his round with another birdie to put daylight between himself and the rest of the field.
The conditions improved as the day wore on – play was suspended for 20 minutes early in the morning – but nobody was able to topple McIlroy from the top of the leaderboard.
Australian Jason Day and American Jim Furyk are his nearest challengers after they moved up to eight under late in the evening.
Day played the front nine in five under, with three birdies and an eagle on the seventh, and he then finished his round off with back-to-back birdies - after his only bogey at the 15th - for a 65, the best round of the day.
Furyk also signed off with birdies at the 17th and 18th for a 68 which put him back within a shot of McIlroy after a mid-round wobble when he bogeyed the 10th and 12th.
Ryan Palmer, who shared the overnight lead with Lee Westwood and Kevin Chappell, was another to birdie the final two holes, after battling against the worst of the weather early on for a one-under 71 which put him on seven under alongside compatriot Rickie Fowler and Finland's Mikko Ilonen.
Fowler continued his excellent record in the majors this season with a round of 66 which included eight birdies and three bogeys while Ilonen, who won the Irish Open earlier this year, was another to birdie 17 and 18 in a round of 68.
Phil Mickelson is also well-placed to mount a challenge over the weekend after a crowd-pleasing eagle on the 18th which gave him a four-under total of 67 and moved him up to six under.
Westwood, who opened with a 65, was eight under after 10 holes but he then dropped four shots in four holes from the 13th, a disastrous run during which he twice found water, before closing with a birdie for a 72 which left him on five under.
Chappell faded even further with a 74 and required treatment on his back at one stage.
Woods misses cut
Tiger Woods was among those to miss the cut - for the fourth time at a major - after struggling round in 74 for the second day running.
The former world No 1 appeared to be troubled by his back once again after a double-bogey six on the sixth hole and there was speculation that he could withdraw after completing nine holes.
However, he continued on the back nine, playing conservatively, and even managed a couple of birdies at the 15th and 18th to finish on six over, five shots adrift of the cut which came at one over.
Martin Kaymer, Padraig Harrington, Keegan Bradley, Jordan Spieth and Thomas Bjorn are also among those who will have the weekend off.