Spieth, 23, blew a three-shot overnight lead by the turn and trailed Kuchar after dropping a shot on the 13th.

But he wrestled back the lead with a run of birdie, eagle, birdie, birdie to finish on 12 under and win his third major after the Masters and US Open.

The American is the second player after Jack Nicklaus to win three of golf's four majors before the age of 24.

The world number three is the youngest Open winner since 22-year-old Seve Ballesteros won the first of his three titles in 1979.

Spieth, who either led or tied for the lead after every round, carded a one-under-par 69, with fellow American Kuchar's 69 leaving him on nine under.

Spieth will have the opportunity to complete the career Grand Slam at the PGA Championship in August.

"This is absolutely a dream come true," said Spieth, who receives $1.8m (£1.4m) in prize money.

"I drank some wine from the Claret Jug when Zach Johnson won it two years ago and people said that was bad luck.

"I started to believe them too after nine holes today."

Twenty-one-year-old Li Haotong of China played the second lowest round of the tournament with a 63 to climb to third place on six under.

Northern Ireland's Rory McIlroy hit a three-under 67 to tie for fourth on five under, alongside Spain's Rafael Cabrera-Bello (68).

England's world number 172 Matthew Southgate finished on four under for a tie for sixth place, along with South Africa's Branden Grace, who carded the first 62 in a men's major in the third round.

BBC