Spaniard Izan Guevara took the victory at the Australian Moto3 Grand Prix to more than the necessary 50 points clear of two rounds from the end of the world championship.
The 18-year-old GasGas Aspar rider has dominated this year of world championship, winning six races and triumphing at Phillip Island by 0.345 seconds over KTM's Deniz Oncu.
"It's great to be world champion. Thanks to my team and my family," he said.
Former junior world champion, he has extended his lead at the top of the standings to 65 points behind team mate Sergio Garcia, who finished third.