This was always going to be a tough match to call and the morning’s opening exchanges illustrated just how evenly matched the two finalists were.
Björnsson made an early statement of intent with a birdie on the very first hole to steal a march but he could never get more than one-hole ahead.
When Libera trundled in a 20-footer for a birdie on the 11th, the Swede grabbed the lead for the first time, but it was a fleeting advantage and the sparring duo would eventually finish all-square after 18 holes.
It was Libera, aiming to become the sixth Swedish winner and the third in the last five years, who took control in the afternoon and moved into a three-hole lead around the turn.
For a spell, Björnsson became slightly ragged but showed his fighting spirit and refused to give in.
He knocked a fine approach into a couple of feet at the 29th to pinch a hole back but he got into trouble on the 30th when his pitch up the slope to the flag rolled back to his feet and he slipped to a double-bogey.
Three-down with six to play, Björnsson rallied again and made a birdie from five feet on the 31st to reduce the deficit.
Libera’s lead became just one on the 33rd when Björnsson conjured a terrific shot from the greenside bunker and saved his par as his rival stumbled to a bogey.
The vigorous fist pump which followed the Icelandic teenager’s par-putt underlined the significance of the moment. “That was another of the best shots I’ve ever hit,” he said of his recovery from the sand.
As the tension mounted, Björnsson’s comeback was complete on the 35th when Libera lost his tee-shot in a bush down the left side of the fairway and ended up conceding the hole.
With both players finding bunkers up the 36th, it came down to a shoot-out with the putters on the final green.
Björnsson’s ten-footer for par kissed the cup and he was left with his head in his hands, but Libera also missed from just inside him and Björnsson was handed a reprieve.
He would seize his moment on the 37th with a match-winning moment that was worthy of a true champion.