Tao Geoghegan Hart kept his cool to win the Giro d'Italia by 39 seconds ahead of Jai Hindley to become the second British rider in three years to win La Corsa Rosa.
After 20 stages and over 85 hours in the saddle, nothing split the two top riders going into Sunday's decisive 15.7km individual time trial in Milan. But 25-year-old Geoghegan Hart stuck to the script and put in a superior effort against the clock after a nerve-wracking eighteen minutes decided the 3,360km three-week race.
London-born Geoghegan Hart became the first rider in the Giro's 111-year history to stand atop the final podium without once wearing the famous maglia rosa during the race. He becomes the fifth Ineos Grenadiers rider in a decade to win one of cycling's Grand Tours after compatriots Bradley Wiggins, Chris Froome and Geraint Thomas, and the Colombian Egan Bernal.
Hindley, who would have become the first Giro winner from Australia, was last down the ramp in Milan, but could not match his rival en route to the finish beside the Duomo di Milano. The 24-year-old was joined by Sunweb teammate Wilco Kelderman on the final podium, the Dutchman finishing 1'29" down on the overall winner.
Victory on the day went to another Ineos Grenadiers rider, the time trial world champion Filippo Ganna, who stormed to his fourth stage win of the race to complete a time trial hat-trick and secure his team's seventh triumph of an extraordinary race.
Italy's Ganna, riding his maiden Grand Tour, completed the 15.7km course in a time of 17:16, 32 seconds quicker than Belgium's Victor Campenaerts (NTT Pro Cycling) and Australian teammate Rohan Dennis.
Fourth place for Joao Almeida (Deceuninck Quick-Step) saw the 22-year-old Portuguese debutant rise above Spain's Pello Bilbao (Bahrain-McLaren) into fourth on the final general classification.
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But the day belonged to Geoghegan Hart who, like his rival Hindley, entered the 103rd edition of the Giro with no ambitions to leave it in pink. Following the withdrawal of Welsh teammate Geraint Thomas after a nasty fall in the opening weekend in Sicily, Geoghegan Hart saw a door open – and jumped right through it.
Victory in the Dolomites at Piancavallo in Stage 15 saw Geoghegan Hart rise to fourth place ahead of the final week, before he and teammate Dennis turned the race on its head during Thursday's extraordinary display of power over the Passo delle Stelvio in Stage 18.
Despite finishing behind Hindley at the finish at Langhi di Cancano, Geoghegan Hart moved within 15-seconds of Kelderman's lead – before his second stage win at Sestriere in the race's penultimate stage saw the Briton draw level with Hindley in the standings to set up a nail-biting finale in Milan.
'Never in my wildest dreams did I think I'd win a Grand Tour' - Giro champion Geoghegan Hart
Asked how he felt to be Britain's latest Grand Tour winner, and a second Giro winner after Froome, a shell-shocked Geoghegan Hart said: "Bizarre, to be honest."
Not in my wildest dreams did I imagine that this would be possible when we started in Sicily. All my career I've dreamed about being top five or ten in a race of this stature, so I think it's going to take a bit of time for this to sink in.
Pressed on whether he could become the next big thing in British cycling after becoming the latest rider, following 2018 Vuelta a Espana winner Simon Yates, to strike gold on the centre stage, Geoghegan Hart remained grounded while delivering a passionate appreciation of his sport.
"I don't know and I don't really care. I'm just going to enjoy this. It's really incredible. I'm going to stay the same person, I'm going to stay as professional as I believe I always have been, dedicated, waking up every day looking forward to riding my bike, loving my life and being grateful for the honour and the amazing position and privilege that I'm in to be in this position on this team and at these beautiful races."
Tied at the top before the final stage, Hindley wore the pink jersey and Geoghehan Hart the white as they started their individual races of truth at a three-minute interval. The Briton looked smoother in the saddle and passed through the intermediate check after 10.2km with a 22-second advantage over his adversary, which grew to 39 seconds at the finish.
Hindley admitted that it was "super disappointing" to lose both jerseys on the last day of the race. "It's super hard to take but I think, when I look back, I'll be super proud of the way the team and I rode the last three weeks," the Sunweb rider said. "It's a massive step forward in my career."
With his overall victory, Hackney's Geoghegan Hart also secured the white jersey as the race's best young rider. Ineos Grenadiers won the team classification thanks to their seven stage wins, the overall win for Geoghegan Hart and a career-high 18th place for Ben Swift.
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Ruben Guerreiro made history for Portugal after becoming the first man from his nation to win a classification jersey in the Giro, the EF Pro Cycling Stage 9 winner – a former youth teammate of Geoghegan Hart at the Axeon Hagens Berman development team – winning the blue king of the mountains jersey.
An excellent race for the Portuguese also saw tyro Almeida secure a top-five finish after wearing the pink jersey for no fewer than 15 days in his Grand Tour debut for Deceuninck Quick-Step.
Frenchman Arnaud Démare (Groupama-FDJ) was the stand-out sprinter of the race with four victories that earned the French champion the maglia ciclamino ahead of Bora-Hansgrohe's Peter Sagan, who ended a long 15-month wait for a win in swashbuckling fashion in a sodden Stage 10.
But the 103rd edition of the Giro will forever be remembered as the race where Tao Geoghegan Hart came of age. Entering as a domestique for teammate Thomas, the 25-year-old helped turn things round for Ineos, winning two summit finishes before coming through the tightest finish in Grand Tour history to become the fifth British winner of one of cycling's major stage races.
Coming one month after a 21-year-old Tadej Pogacar won the Tour de France, this Giro will also mark the latest changing of the guard of what has proved to be an extraordinary season for cycling's new generation. There was no place for the veterans Jakob Fugsang and the former double champion Vincenzo Nibali in the final top five, with three of the top four all 25 years or younger and fighting for both pink and white.