Branden Grace hits his tee shot on the 9th hole during the first round of the RBC Heritage golf tournament. at Harbour Town Golf Links. Mandatory Credit: Jason Getz-USA TODAY Sports

South African Branden Grace delivered a final-round master class to clinch a long expected first victory on the PGA Tour by two shots at the RBC Heritage in South Carolina on Sunday.

The world number 14, who thrust himself into the limelight at the game's highest level with top-four finishes last year at the U.S. Open and PGA Championship, closed with a superb five-under-par 66 at the Harbour Town course on Hilton Head Island.

Helped by pinpoint distance control with his irons and brilliant putting on lightning-fast greens, Grace mixed seven birdies with just two bogeys to post a nine-under total of 275 in the first PGA Tour event after last week's Masters.

Third-round leader Luke Donald of England, striving to end a four-year title drought on the U.S. circuit, carded a 71 to share second place with Scotland's Russell Knox, who signed off with a 67 on a sun-bathed afternoon.

(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Andrew Both)