Miguel Oliveira has taken a stunning victory after a dramatic Catalan GP which saw Fabio Quartararo demoted to fourth at the end.
The drama started before the lights had even gone out after Jorge Martin crashed at Turn 5 on the sighting lap, meaning he had to start from the pits on his spare bike.
Quartararo got a good start off the line but as expected Jack Miller powered past the Frenchman on his Ducati and led by Turn 1.
Quartararo kept going backwards at Turn 1, who dropped to third as Oliveira got past at Turn 2.
Mir got off to a strong start from tenth on the grid, the Suzuki rider found himself up to fourth mid-way around the first lap.
Miller controlled the first lap of the race but then ran wide at Turn 4 on lap 2, which allowed Oliveira to slip from and take the lead of the Catalan GP.
It was expected that Quartararo would be dominant in the race, but the Yamaha rider made a small mistake on lap 2 which dropped him to fifth as Mir and Aleix Espargaro made their way through.
Espargaro then set off to get past Mir and eventually passed the Suzuki at the start of lap 4, the Spaniard had a brief battle with Miller but could not pull off a move for third.
The first incident of the race came on the fifth lap, Pol Espargaro dropped his Honda at Turn 5.
Quartararo started to make his way back to the lead on lap 7, getting up to second and past Mir in the second sector.
Marc Marquez found himself fighting towards the front after starting 13thon the grid, but the Spaniard could only get as far as the eighth lap as he fell at Turn 10, retiring from the race after running in the top seven.
A long-lap penalty was given to Taka Nakagami who cut the Turn 1 and Turn 2 section and failed to give up the time gained, meaning it was a race to forget for the Japanese rider.
On lap 10, Oliveira had a lead of 0.5s but by the next lap Quartararo had cut that gap to just 0.2s, passing the KTM at Turn 5 on lap 12 for the lead.
The Aprilia of Espargaro had an unfortunate fall at Turn 10 on lap 11 which forced him to retire from the race.
It didn’t take long for Oliveira to respond however, as he placed his KTM perfectly at Turn 1 on the 14th lap to retake first place.
Johann Zarco also began to put on a charge from lap 14, who passed Miller at the start of the lap and then took third from Mir on lap 16.
Valentino Rossi’s woes continue in 2021, the Italian fell at Turn 10 on the 16th lap, Iker Lecuona also fell on the next lap at Turn 13.
The drama began at the front in the closing stages of the Catalan GP, as Zarco closed in on Quartararo and then passed his compatriot at Turn 1 on lap 22. Quartararo then lost the front briefly coming out of the corner, which forced him to pick the bike up and cut across Turn 2.
The Yamaha rider then had another problem on his hands on the same lap, as his leathers came completely open, meaning he was riding around with his chest completely vulnerable had he crashed.
Zarco then closed up on Oliveira on the last lap, but as they crossed the line at the chequered flag the KTM rider held on to take his first victory this season after a podium last time out in Italy.
Quartararo held on to third from Miller, but a three second penalty for gaining time after cutting Turn 2 on the 22nd lap demoted him to fourth, meaning the Ducati of Miller rounded off the podium.
Mir crossed the line to finish in fifth place, with Maverick Vinales and Pecco Bagnaia seventh and eighth.
Brad Binder ended the Catalunya GP in eighth with Franco Morbidelli ninth and a very impressive ride from Enea Bastianini put him tenth.
Alex Marquez finished as the top Honda bike in 11th, Luca Marini and Taka Nakagami ended in 12th and 13th.
Jorge Martin finished 14th after crashing on the sighting lap ahead of Lorenzo Savadori who was the last of those to finish the race.
Lecuona, Rossi, the two Espargaro brothers, Marc Marquez and Danilo Petrucci did not finish.