(Reuters) - American Michael Kim sparked into life late on his back nine to build a five-stroke lead after the third round of a marathon day at the John Deere Classic on Saturday.
Celebrating his 25th birthday, Kim finished his third round with four straight birdies to sign for a seven-under-par 64 that put him on an imposing 22-under for the tournament.
Kim endured a long day at TPC Deere Run in Silvis, Illinois, arriving at the course early to finish his second round before taking a nap during a two-and-a-half hour weather delay, then returning to the course to add three birdies and a bogey.
Play was again suspended with Kim on the 14th hole of his third round but he returned to complete a stellar day and remain on course for a first PGA Tour victory.
"I'm pretty used to rain delays from playing on the (second tier) Web.com Tour," Kim told reporters.
"This year has been probably a record of so little rain delays. I'm comfortable going in and going out -- I felt good. I can just relax in the morning, take it easy. I'm looking forward to tomorrow."
Fellow American Bronson Burgoon is his closest challenger at 17-under after completing a five-under-par 66 that included an eagle on the par-five second hole and three straight birdies to close his round.
"I don't know how I finished the way I did," said Burgoon, who had to complete the last three holes of his second round early on Saturday morning.
"I warmed up four times today. It was a grind out there. Obviously, Michael is playing really well. I was playing pretty good myself. So, I'll go get some rest and looking forward to tomorrow."
Australian Matt Jones (16-under) and American Harold Varner III (15-under) also recorded rounds of 66 to stay in contention.
Jones, 38, has one PGA Tour victory, the 2014 Shell (LON:RDSa) Houston Open, while the 27-year-old Varner is flirting with a first ever PGA Tour win for the second consecutive week after finishing tied for fifth at Greenbrier.
Argentinean Andres Romero shot a 64 and is one of two players at 14-under.