American Collin Morikawa produced an ice-cool final round to win the British Open by two strokes on a blazing hot afternoon at Royal St George’s on Sunday.

The 24-year-old began the day a stroke behind Louis Oosthuizen but played faultless golf in a four-under round of 66 to overhaul the South African and resist resurgent fellow- American Jordan Spieth.

Morikawa barely missed a fairway all day as he made four birdies and showed incredible composure when he came under pressure late in the day.

It was his fourth sub-par round of the week as he ended on 15-under 265 — his remarkable consistency born out by the astonishing statistic of only four bogeys all week.

This was Morikawa’s second major, having won the PGA Championship last year.

Spieth started his final round badly with two bogeys in his first six holes but an eagle at the seventh launched a gallant chase of Morikawa.

He finished on 13 under with Oosthuizen ending in a tie for third with Spain’s Jon Rahm.