Xander Schauffele said a "sense of calm" helped him win the British Open on Sunday as the American claimed his second major just two months after triumphing at the PGA Championship.

The 30-year-old Californian delivered a faultless, zen-like six-under-par final round at Royal Troon to emerge from a congested leaderboard and clinch the Claret Jug.

Schauffele finished on nine-under par for the championship, two shots ahead of England's Justin Rose and Billy Horschel of the US.

Schauffele, who registered a major record of 21-under-par to win the PGA at Valhalla in May, is the first player to win two majors in a year since Brooks Koepka in 2018.

His victory on the west coast of Scotland completes an American clean sweep of the game's biggest titles in 2024.

"I thought (winning the PGA) would help me and it actually did. I had this sense of calm, a calm I didn't have when I played earlier at the PGA," said Schauffele.

"I was telling my caddie Austin (Kaiser) that I felt pretty calm coming down the stretch and he said he was about to puke on the 18th tee."

"I just told myself to just hit it down there and keep moving along," added the world number three, who described clinching the Open as a "dream come true". (AFP)