Henrik Stenson's quest for a second Major Championship in as many weeks was set to go right to the wire as the final round of the US PGA Championship moved towards its conclusion on a marathon day at Baltusrol Golf Club.
Storms on Saturday meant that the leading contenders faced 36 holes on day four in New Jersey but Stenson, Jimmy Walker and Jason Day showed no ill effects as they did battle on Sunday afternoon.
Walker came into round four with a one-shot lead at 11 under and he maintained that at the turn with nine straight pars, with defending champion Day and Stenson leading the chasing pack.
The Swede lifted the Claret Jug just 14 days ago at Royal Troon and is looking to record a remarkable summer as he heads to the Olympics in Rio next week.
Branden Grace set the clubhouse target at nine under after a 67 and he was a shot clear of Brooks Koepka and Hideki Matsuyama.
Grace made an early move with birdies at the second, fourth and seventh to turn in 33 and join the group at nine under.
Stenson required a nervy eight-footer on the first but managed to save par, a feat that was not matched by Day who dropped his first shot in 21 holes after going a long way right off the tee to hand Walker a two-shot lead.
Grace then maintained his charge with an approach to six feet on the 13th and he moved into double figures.
Day was ragged off the tee again on the third and dropped another shot and, while Walker also went wide with his first shot on the same hole, the 37 year old recovered well to save par.
Stenson then played a brilliant shot out of the rough to set up a birdie on the sixth while Day made his first birdie of the round on the fifth.
Grace then bogeyed the 16th and that took the wind out of his sails but he saved par on the 18th after finding the water to set the target at nine under.
A sensational tee-shot from Day on the ninth left the Australian with a tap-in birdie and he was back within one of Walker who made a few testing putts as he turned with nine pars.
Koepka had made ten pars in a row but he got in serious trouble in the trees on the 11th to record a bogey.
Tyrrell Hatton's 68 was his third round of the week in the 60s and the Englishman was on course for an impressive finish at seven under after his tie for fifth at The Open Championship.
Padraig Harrington - the 2008 champion - was then at six under after following up his brilliant 65 with a 68.
