Alexander Zverev produced a majestic performance to claim the biggest title of his career and deny Novak Djokovic a record-equalling ATP Finals success on Sunday.
Djokovic had not been broken in London or dropped a set this week, but the magnificent Zverev struck a big blow for the next generation by winning a high-quality final 6-4 6-3.
World number one Djokovic was unable to match Roger Federer's tally of six triumphs at the season-ending event as his 21-year-old opponent rose to the occasion with a nerveless display.
The German was booed after stopping mid-point in a second-set tie-break when a ballboy dropped a ball during his semi-final win over Federer on Saturday, but he turned jeers into cheers by denying Djokovic a glorious end to a resurgent season.
Zverev, comfortably beaten by Djokovic in the round robin stage on Wednesday, won 79 per cent of points on his first serve as he claimed a fourth title of a season in which he has won more matches than any other player.
The third seed showed no signs of nerves on the big stage as both players started with vigour, serving superbly and trading punches from the baseline.
There was not a sniff of a break point in a service masterclass until Djokovic let his usual high standards slip at 4-4, drilling a forehand long and crashing another into the net to give Zverev the chance to serve out the set.
The world number five grasped his opportunity emphatically, firing down three aces and clenching his fist after another wayward groundstroke saw Djokovic lose a first set of the week.
Zverev maintained his momentum with the 14-time grand slam champion looking vulnerable and broke in the first game of the second set with a searing forehand winner to end an epic rally.
The Serbian broke straight back, but gifted his youthful opponent the initiative immediately with a poor attempted drop shot followed by a tired looking forehand into the net.
Zverev consolidated the break on this occasion to lead 3-1 and Djokovic was unable to find a way back.
A fittingly sublime backhand winner from Zverev ended a pulsating contest, the two rivals embracing after the new champion had dropped to the court with a weight seemingly lifted off his shoulders.
Zverev  bt Djokovic  6-4 6-3
Zverev - 23/18
Djokovic - 7/20
Zverev - 10/3
Djokovic - 1/1
BREAK POINTS WON
Djokovic - 1/1
FIRST SERVE PERCENTAGE
Djokovic - 60
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Zverev - 79/54
Djokovic - 74/35
Zverev - 57
Djokovic - 46
|LeBron trumps Wade in last dance, Curry scores 38 points|
|Seahawks secure dominant win over Vikings|
|Iniesta visits Messi and former club Barcelona|
|Drake makes plea for ball thrown into stands after Miami miracle|
|´Toughest pretty boy I´ve ever met´ - Langer dismisses Paine concerns|
|Van Dijk says Liverpool can challenge for double ahead of Napoli decider|
|Hazard: I´ve always loved Real Madrid|
|Yankees interested in Machado, not Harper - Cashman|
|Warriors´ Curry believes moon landing was faked|
|76ers star Butler suffers strained groin|
|Brady: Patriots still have a lot of football to play|
|´No one died´ - Belichick´s message to Patriots after stunning loss|
|Silva lauds Digne after stunning free-kick|
|Aduriz joins Messi, Ramos in LaLiga history books|
|We have a plan - Ravens coach Harbaugh prepared for Flacco return|
|´It´s difficult to accept´ - Gracia calls for introduction of VAR|
|LaLiga press on with overseas match plan despite Barcelona withdrawal|
|PSG open Coupe de France defence at fifth-tier Pontivy|
|Hazard backs Sterling as Neville reveals England star´s Euro 2016 concerns|
|Everton 2 Watford 2: Digne salvages draw with 96th-minute free-kick|
|Barcelona could ´steal´ Kane, says Pochettino|
|Oakland Raiders fire general manager McKenzie|
|Struggling Villarreal appoint Garcia Plaza as Calleja successor|
|Warriors assign Cousins to G League team|
|Barcelona pull out of plan to play LaLiga game in Miami|
|Pochettino to keep an eye on Inter when Spurs face Barcelona|
|Pochettino confirms Walker-Peters set to start against Barcelona|
|Denver Nuggets add free agent Young|
|Topping Group A no magic wand for an easy knockout draw, says Simeone|
|The cake has been made, now we need the cherry - Ancelotti targets repeat at Anfield|
|Lloris braced to face ´one of the best in history´ in Messi|
|Tuchel expects Neymar to face Red Star|
|Foden signs Manchester City deal to 2024|
|It happened to me! - Valverde laughs off Dembele timekeeping|
|´Projecting´ an Argentina return? Messi met with AFA president and Scaloni|
|Erasmus expects to leave head coach role after World Cup|
|Chelsea issue suspensions pending investigation into Sterling incident|
|Kane is extraordinary – Valverde hails reported Barcelona target|
|Man behind Naomi Osaka´s rise wins WTA Coach of the Year|
|England name unchanged Test squad as Willey returns for West Indies ODIs|
|Spalletti: No issue with Icardi watching Superclasico in Madrid|
|Klopp confirms 2013 talks with ´chatty´ Napoli president De Laurentiis|
|Sri Lanka spinner Dananjaya suspended due to illegal action|
|His reaction was just brilliant – Klopp praises Sterling for response to abuse|
|Gomez renewal a ´smart decision´ for both parties – Klopp|
|Magnificent Molinari named European Golfer of the Year|
|Barcelona best option for Frenkie de Jong, insists midfielder´s father|
|Gronkowski on Miami Miracle: ´Got to make that tackle´|
|Tottenham youngster Walker-Peters signs on until 2023|
|Juventus ´more of a family´ than Real Madrid - Ronaldo|
|Kingsley Coman contemplates retirement if injury nightmare continues|
|McVay ´sick´ over offensive failings as Rams coach takes blame for loss|
|Calleja axed as Villarreal coach|
|Kenyan Drake on Miami Miracle: I couldn´t let Gronk tackle me!|
|Ronaldo: I deserved Ballon d´Or, the numbers don´t lie|
|Rugby Australia to make Cheika decision this month|
|England defender Gomez signs new Liverpool deal|
|Ronaldo wants to see Messi follow him to Italy|
|Neymar happy to play in any position for PSG - Draxler|
|Paine insists he is ´fine´ after taking blow to finger|
|Ponzio: River players will be ´idolised´ for Libertadores success|
|Champions League permutations: How Inter, PSG and Liverpool can progress|
|Kohli: India were better and deserved to win|
|Bears shut down Goff, Rams|
|India survive dramatic finish against Australia|
|Klopp calls for electric Anfield atmosphere against Napoli|
|Saints clinch back-to-back NFC South titles, Bears trump Rams|
|Bucks improve to 2-0 against Raptors with win in Toronto|
|Black Caps include Patel for Sri Lanka Tests|
|Maidana: River want Real Madrid clash|