Jorge Lorenzo became Spain's first ever double premier-class grand prix champion by clinching the 2012 MotoGP crown at Phillip Island in Australia on Sunday.
The only Yamaha rider to win races this year, Lorenzo battled reigning double champion Casey Stoner for the first half of the season and later the other Repsol Honda of Dani Pedrosa.
25-year-old Lorenzo came into the penultimate round needing to beat Pedrosa to avoid a final round showdown at Valencia.
Having not finished ahead of Pedrosa on track since July, the pressure was on, but it was Pedrosa who blinked first, crashing while leading on lap two of the race.
Lorenzo then held a safe second place to the finish, continuing his extraordinary record of finishing no lower than runner-up in all but one of the 17 races this season, the exception being when he was taken down out at Assen.
“I'm really happy with this championship, because only we know how difficult it is to fight with riders like Casey and Dani, and to fight with factories like Honda,” said Lorenzo, his voice showing signs of emotion.
“It is very hard. You must be very consistent. Never make a mistake. Always try to finish all the races. Stay very focussed.
“So today is a special day and I want to thank all my team, Yamaha, my family, friends, sponsors and everyone that believed in me and wanted me to win. Thank-you very much.”
Lorenzo - who won his first MotoGP title on an 800cc Yamaha in 2010 - and Pedrosa have both won six races this year, with the retiring Stoner now up to five wins.
The next best Yamaha rider behind Lorenzo in the championship is fourth place Andrea Dovizioso, who has scored 208 points compared with 350 for Lorenzo.
Lorenzo, also a double champion in the 250cc class, will be re-joined by Valentino Rossi at Yamaha next season.