Jorge Lorenzo's third race victory in three weekends means he could skip the next two races and still be leading the MotoGP World Championship.
Repsol Honda riders Dani Pedrosa and Andrea Dovizioso both joined Lorenzo in leading Sunday's Catalan Grand Prix, but couldn't keep their RCVs on track.
Pedrosa got the holeshot, then ran wide at the very first turn - dropping him down the order - while Dovizioso led on lap four and stuck with Lorenzo after the Spaniard got back ahead, only to fall from a close second place on lap 15 of 25.
Ducati's Casey Stoner, the only other threat to Lorenzo, ran wide at the start of lap six and spent much of the race unsuccessfully challenging Pedrosa for what became second.
Lorenzo was thus left to cruise to a five-second home victory, marking his fifth win from seven starts and handing him a 52 point title lead over Pedrosa heading into the German Grand Prix in two weeks' time.
"This is very special," said Lorenzo, who lost out to team-mate Valentino Rossi at the final turn of last year's race. "After losing so closely last year I was happy but not completely so and today I can say I am completely happy, winning here at my home race.
"It was very difficult today because it was so hot and the front tyre was sliding a lot. I thought I was going to have a big battle with Dovizioso because he was pushing very hard but then he crashed and I was alone; it was lucky for me because then I was able to take it more gently to the finish.
"I think I rode a clever race today. I am so grateful to my team and to everyone at Yamaha and Bridgestone because they are working so hard to make our bike competitive at every track. I also want to say thank you to all the fans that came to watch today, it is a great feeling for me to win here in front of them all."
Lorenzo has taken a hat-trick of wins once before in his career, in his 250cc days, and is the first Yamaha rider to take three wins from three poles since Eddie Lawson in 1986.