Alex Marquez clinched the Moto3 world championship in an enthralling Valencia finale, despite title rival Jack Miller winning the race.
With Marc Marquez having already wrapped up the 2014 MotoGP title, the Marquez siblings become the first brothers ever to hold grand prix motorcycle world championships at the same time.
Marquez needed a podium finish to seal the crown in the Moto3 decider, which he spent in a huge battle with Miller, Isaac Vinales, Niccolo Antonelli, Efren Vazquez and the title rivals' team-mates Alex Rins and Danny Kent.
Contact with both poleman Antonelli and Miller sent Marquez down the order at different points, with Miller also falling as low as sixth following another brush with his title rival.
Vinales, cousin of 2013 Moto3 champion Maverick, escaped into a 1.6-second lead as the pack behind delayed itself, but once back to second, Miller was able to hunt him down and reclaim the lead on the final lap.
Marquez had made it into a safe third by then too, but he had to resist pressure from the fast-closing Kent to hang on and become champion by two points.
The 18-year-old will now move into Moto2 with Marc VDS next season, while Miller jumps straight to MotoGP with LCR Honda.
LEADING RESULTS - 25 LAPS:
|1||Jack Miller||Red Bull KTM Ajo||KTM||40m10.983s|
|2||Isaac Vinales||Calvo Team||KTM||0.155s|
|3||Alex Marquez||Estrella Galicia 0,0||Honda||0.955s|
|4||Danny Kent||Red Bull Husqvarna Ajo||Husqvarna||1.572s|
|5||Alex Rins||Estrella Galicia 0,0||Honda||2.251s|
|7||Niccolo Antonelli||Junior Team GO&FUN Moto3||KTM||3.620s|
|8||Miguel Oliveira||Mahindra Racing||Mahindra||4.216s|
|9||Brad Binder||Ambrogio Racing||Mahindra||4.248s|
|10||Karel Hanika||Red Bull KTM Ajo||KTM||4.363s|
FINAL CHAMPIONSHIP STANDINGS: