Francesco Bagnaia claimed the MotoGP crown in the season-ending Valencia Grand Prix on Sunday to pull off the greatest title turnaround in the championship's history.
The Ducati rider, who trailed outgoing champion Fabio Quartararo by 91 points mid-season, completed his astonishing comeback with a ninth place behind race winner Alex Rins.
"World champion - it sounds good" beamed Bagnaia, known as 'Pecco'.
"That was the hardest race of my life.
"I was struggling. My aim was to be in the top five, but I started to struggle after a few laps, but the most important thing is we are world champions," the 25-year-old added.
Among those rushing to congratulate him was his mentor, Italian motorcycling legend Valentino Rossi, the last Italian to win the MotoGP title in 2009.
Also on hand was Giacomo Agostini, who was the last Italian to take the championship on an Italian bike 50 years ago.
Ducati's last world championship came back in 2007 courtesy of Casey Stoner.
Back in June, Quartararo looked sure to defend his crown after success on his Yamaha in Germany.
His subsequent collapse was painful for his fans as Bagnaia reeled in the Frenchman with the help of four consecutive wins to take a 23-point lead going into the season finale in Spain.
That left the French rider needing to win, and Bagnaia finish out of the top 14, to retain his crown, a mission that was to prove impossible.
"I have no regrets because I gave 100 percent today, and when you lose a title like that you have to see the positives," said Quartararo.
"In the next four months, I'll be even more determined to make an effort and prepare myself better."
Quartararo could only muster fourth behind Rins, who was supplying Suzuki with a fairytale result in their MotoGP swansong with the Japanese constructor pulling the plug on their MotoGP involvement.
"We couldn't sign off any better than this," said Rins.
"I'm so proud, I've learned so much with Suzuki and now I'm going to start a new chapter (with Honda-LCR next season)," he added.
KTM's South African rider Brad Binder and pole-sitter Jorge Martin, a Spaniard on a Ducati Pramac, completed the podium.
- Ducati red -
Bagnaia, the Moto2 champion in 2018, sealed his first MotoGP championship 17 points clear of Quartararo on 265 points after a tense deciding leg of the 20-race season. Enea Bastianini, on a Ducati-satellite bike, finished third in the standings.
Quartararo and Bagnaia's bikes came into contact in an early tussle for fifth at the Ricardo Tormo circuit and a wing ripped off the Ducati.
Bagnaia's only real danger was a crash, a fate that befell six-time champion Marc Marquez, and Jack Miller.
The Italian's triumph sparked ecstatic celebrations at the circuit and in the square of his home town Chivasso -- turned Ducati-red with flares and flags.
Bagnaia, who when not riding is a regular at Juventus games, wasn't the only one celebrating as Augusto Fernandez claimed the Moto2 crown after his only rival, Honda's Japanese rider Ai Ogura, crashed out.