Brazilian 18-year-old Joao Fonseca completed a terrific comeback to defeat the USA's Learner Tien in four sets and win the Next Gen ATP Finals title in Jeddah.
The 2006-born South American fell a set down in Sunday's showpiece, but after restoring parity in a nail-biting second-set tie-breaker, he prevailed 2–4, 4–3[8], 4–0, 4–2 in one hour and 27 minutes.
Fonseca - the lowest-ranked player at this year's event - became the second-youngest player in history to take home the Next Gen crown, only older than Jannik Sinner when the current world number one won the title in 2019.
As the 18-year-old also went through the competition without losing a single match, he pockets the maximum amount of prize money on offer, a whopping $526,480 (£418,838).
Rafael Nadal was present in Saudi Arabia to witness Fonseca conquer the Next Gen ATP Finals, which piled added pressure on the teenager's shoulders, as he said after the match: "I was really nervous before the match. I knew it was going to be so difficult.
"I played a final against Learner in juniors [at the 2023 US Open] and I know the way he can play. He is such a nice guy and a great player, so I knew it was going to be difficult, mentally and physically. But I got my way through."
How Fonseca battled past Tien to win Next Gen ATP Finals
Fonseca had already navigated his way past Tien in four sets during the round-robin stage, but early nerves were evident on the Brazilian's side, as numerous unforced errors in the first game gifted the American an immediate break.
There was little to choose between the two fledgling foes in the second set, but it was Tien's turn to make a raft of errors in the tie-breaker, both wasting a set point and being pegged back to 1-1 in the match by three consecutive unforced mistakes.
A fired-up Fonseca subsequently went on the warpath, forcing a break to love in the first game of the third set, where he restricted Tien to just three points in total en route to a brilliant bagel.
At 2-1 up in the match, the Brazilian remained unflappable on serve and broke Tien one final time in the fifth game of the fourth set, before bringing up match point with a 133mph ace.
Fonseca needed just the one opportunity to etch his name on the trophy, as Tien went for a down-the-line forehand but undercooked his attempt, at which point Fonseca collapsed onto the court in euphoria.
The 18-year-old follows Chung Hyeon, Stefanos Tsitsipas, Carlos Alcaraz, Sinner, Brandon Nakashima and Hamad Medjedovic as the seventh winner of the Next Gen ATP Finals, which was first held in 2017.
