(Reuters) - Taiwan's Pan Cheng-tsung won his first PGA Tour tournament with a one-stroke victory over Matt Kuchar as world number one Dustin Johnson stumbled badly on the back nine at the RBC Heritage in South Carolina on Sunday.
Pan, who goes by the initials C.T., collected a birdie and two pars on his last three holes to shoot a four-under par 67 and end a tense final round at 12-under 272.
Kuchar, finishing ahead of Pan, used a birdie at the last to also shoot 67 and waited as Pan, ranked 113 in the world, held steady at the end at Harbour Town Golf Links on Hilton Head Island.
Patrick Cantlay (69), Scott Piercy (69) and Ireland's Shane Lowry (70) tied for third at 10-under as overnight leader Johnson shot a six-over 77 to finish at four-under.
World number one Johnson, who started the day with a one stroke lead, had three bogeys and two double bogeys in a five hole stretch.
(Reporting by Gene Cherry in Salvo, North Carolina; Editing by Christian Radnedge)