Alex Rins held off compatriot Alex Marquez to win the Aragon MotoGP on Sunday with another Spaniard Joan Mir finishing third to take the championship lead from Fabio Quartararo.
Suzuki's Rins became the eighth winner in this season's ten races as the vacuum created by the early season injury to reigning champion Marc Marquez has created a volatile and unpredictable title race.
This is the third victory for the 24-year-old Rins who won twice last year but was injured at the beginning of this season.
He sliced through the field after starting 10th on the grid.
"I had a very good start," he said.
The other Suzuki factory rider Mir takes over the championship lead even though he has not won a MotoGP race.
He has 121 points in the championship ahead of Quartararo (115), Spaniard Maverick Vinales (109) and Italian Andrea Dovizioso (106).
"I'm trying to be as consistent as I can," Mir said. "I'm happy to be on the podium."
Frenchman Quartararo, who started from pole, struggled and finished down in 18th place.
One of the riders attempting to fill the void left by Marquez is his younger brother and Honda teammate Alex Marquez who, after a slow start to his rookie season, has finished second in two straight races.
"It's a pleasure to be on podium with a second second place," said Marquez. "Next week we will try harder."
Six-time champion Marc Marquez was overjoyed.
"I am the brother of Alex Marquez," he tweeted in Spanish.
Meanwhile, seven-time MotoGP world champion Valentino Rossi's quarantine after testing positive for Covid-19 means he will also have to miss next weekend's Grand Prix of Teruel at the same Aragon circuit.
"Due to Italian law, Valentino Rossi will be unable to attend the Gran Premio de Teruel event," said a Yamaha team statement.
The 41-year-old Italian, who sat out Sunday's race, has to compete a 10-day quarantine and test negative before he can return to the circuits.
Yamaha said that it would not replace Rossi in Teruel, leaving Vinales to ride alone again at MotorLand Aragon.
Michelin, which supplies MotoGP, also announced on Sunday that one of its technicians tested positive and was placed in isolation along with one of his colleagues.
Rossi was not the only rider forced to miss this weekend due to Covid-19.
In Moto3, young Italian Tony Arbolino must quarantine after coming into contact with a fellow passenger to Spain who tested positive for the virus.
Spaniard Jorge Martin, who rides in Moto2, missed two races in September after a positive test.
Elsewhere on Sunday, Britain's Sam Lowes won the Moto2 race, a week after also triumphing in the rain of Le Mans.
Italy's Enea Bastianini, who was second, took the world championship lead.
Previous leader Luca Marini of Italy fell and is now in third place overall.
Jaume Masia won the Moto3 event from 17th on the grid but Albert Arenas extended his championship lead despite finishing seventh.