SOUTHPORT, England — Jordan Spieth was in the midst of a monumental collapse Sunday that would have made his calamity on the 12th hole in the 2016 Masters seem like a minor misstep on Magnolia Lane.

The three-stroke overnight lead he took into the final round of the 146th British Open had vanished along with any semblance of his best form, and the young Texan looked lost, frustrated and defeated on the ancient land of Royal Birkdale. Then things got worse as his tee shot on the par-4 13th wound up 40 yards to the right of the fairway and disappeared into high, thick grass, forcing him to take a penalty drop. Make that an adventurous, bizarre penalty drop that took 20 minutes, as he decided to take the drop on the driving range by the equipment trucks despite a massive sand dune blocking his vision of the green.

Somehow, someway, Spieth pulled it off.

With a final-round, 1-under-par 69, Spieth, who turns 24 on Thursday, held off playing partner Matt Kuchar to win by three shots and had his name engraved on the shiny, gray Claret Jug that will join his green jacket and silver U.S. Open trophy he captured in 2015.

His total of 268 was 12 under for the tournament.

From the moment he finally hit his approach to the 13th green, Spieth authored the latest chapter in his ever-growing legend. With a remarkable brilliance, Spieth started doing Spieth things and summoned a red-number tear by going birdie-eagle-birdie-birdie to wrestle back the Claret Jug.

His late blitz won him the oldest championship in golf and he became the second youngest player to win the first three legs of the career grand slam.

Spieth is now on the doorstep of history, just a Wanamaker Trophy away from joining Gene Sarazen, Ben Hogan, Gary Player, Jack Nicklaus and Tiger Woods as the only players to complete the grand slam. Spieth’s first chance to join the immortal group comes next month in the 99th PGA Championship at Quail Hollow in Charlotte.