Montmelo - Spain's Marc Marquez, on a Honda, stretched his lead atop the standings after streaking to victory in Sunday's Catalan MotoGP.
It was five-time world champion Marquez's first victory on his home region Montmelo track since 2014 and came hot on the heels of that of his younger brother Alex in the Moto2 class earlier in the day.
French Yamaha rider Fabio Quartararo, just 11 days after undergoing surgery on his arm, started from pole in the seventh MotoGP of the season and eventually came in second, 2.66sec off Marquez.
Marquez benefitted from a fall by Italian rival Andrea Dovizioso to consolidate his lead in the world championship rankings.
His victory came on the 70th anniversary of MotoGP. The competition's first race, the Tourist Trophy of the Isle of Man, was held in 1949 and won by Britain's Freddie Frith.
Alex Marquez, on a Kalex, saw his Moto2 win propel him atop the category's standings.
Marquez clocked 38min 25.678sec to finish ahead of Switzerland's Thomas Luthi, with another Spaniard, Jorge Navarro, rounding out the podium at the Montmelo circuit.
The victory saw Marquez leapfrog Italian teammate Lorenzo Baldassarri in the standings.
There was more glory for Spain in the Moto3 when Marcos Ramirez, on a Honda, notched up his maiden victory, and in doing so became the 12th different winner in the last 12 races in the highly competitive class.
Ramirez took the lead from Honda teammate Kaito Toba after the Japanese, who started 24th on the grid, fell on the final lap.
Despite a last-corner pass attempt from KTM's Spanish rider Aron Canet, Ramirez held on through to the line of a chaotic, crash-marred race.
Spain's Canet heads up the riders' standings, extending his lead from three points before the race to 23, with his closest rival Lorenzo Dalla Porta forced to retire with trouble on board his Honda.