Oakmont - Here are at five outsiders to keep an eye out for at the 2016 US Open, which starts on Thursday at Oakmont:
BROOKS KOEPKA (USA)
Age - 26
World ranking - 16
-- Oddly for an American golfer, worked his way up the pro ranks on the European Tour, winning the Turkish Open in late 2014. Then notched up first win on US Tour in Phoenix. Lost a play-off to Sergio Garcia at the Byron Nelson tournament last month.
MATTHEW FITZPATRICK (ENG)
Age - 21
World ranking - 34
-- England's most promising youngster won the 2014 US Amateur and last year he scored a breakthrough first win on the top pro circuit at the British Masters. Won the Nordea Masters by three strokes at the start of June and is on course for a Ryder Cup debut.
BRANDEN GRACE (RSA)
Age - 28
World ranking - 12
-- The latest product out of the Ernie Els foundation to enter the winners' circle among the top pros. Won four European Tour tournaments in 2012 and was in contention at last year's US Open right up to the end. Recent winner of the Heritage in the United States.
AN BYEONG-HUN(KOR)
Age - 24
World ranking - 27
-- Father and mother both won table-tennis medals at the 1988 Seoul Olympics, An moved to America to improve his golf in 2005 and attended the University of California-Berkeley before turning pro in 2011. In May 2015, he won the BMW PGA Championship at Wentworth but he lost in a playoff at the New Orleans Zurich classic in early May
EMILIANO GRILLO (ARG)
Age - 23
World ranking - 46
-- The last time the US Open was held at Oakmont it was an upset winner from Argentina in the bulky shape of Angel Cabrera. Grillo is the latest golfer to emerge from the Pampas, winning the season-opening Frys-com tournament late last year after taking the Web-com Tour championship title.