Having won the 2020 MotoGP title the previous weekend in Valencia, Joan Mir suffered his worst weekend of the year in the Portimao finale.

Qualifying in just 20th place after an electronics issue, the Suzuki star immediately went on the attack in the race - clashing with Francesco Bagnaia as he carved his way through to twelfth on the opening lap, then hitting the back of Johann Zarco, again at the Turn 3 hairpin.

"I felt it, it was a very slow corner and I didn't know which rider it was," said Zarco, who went on to finish in tenth. "I think fortunately he braked pretty well because the contact was there but quite soft, because he just picked my bike up a little but did not disturb me too much."

Bagnaia had also stayed upright but was then forced to retire with pain in his arm. Meanwhile, Mir's traction control system was damaged in one of the incidents and, with the problem getting worse, he finally called it a day at mid-distance, when in 19th place. 

"It was an unfortunate day. In the first laps I was feeling really good. The adrenaline was making it easy for me to overtake, and it was fun," Mir said. "Then I have to say sorry to Pecco, because in that part I was really aggressive, a bit too much.

"Sometimes I criticise this type of manoeuvre and I was, not dirty, but it was not the best manoeuvre. I'm sorry for that. And then, because of this touch - I don't if it was with Zarco, where I also touched the front, or with Pecco - it affects somehow the electronics of the bike.

"We don't know why, but I didn't have traction control. I was having traction control in some parts, in some parts not. It was really dangerous because I didn't know [what would happen] and I had some big moments during the race. As the tyre was getting used, it was getting worse and worse and worse, and I had to retire.

"It was a shame to finish the season like this, but it is what it is."

The third DNF of the season for Mir, who said the traction control issue was not the same as the electronic problem he suffered on Saturday, meant he finished the year with a 13-point advantage over Petronas Yamaha's Franco Morbidelli.

Mir's problems combined with a bad race for team-mate Alex Rins (15th) meant Suzuki dropped to third in the Constructors' title, behind Ducati and Yamaha.

“This season has been the best I have ever experienced, Joan and Alex did an incredible job," said Suzuki project leader Shinchi Sahara. "We did hope to achieve the ‘triple crown’ and second place in the standings for Alex, but unfortunately this wasn’t possible today after a difficult race. However, it means we have a really big and exciting target for next year. Thank you to the entire Suzuki family, those in the factory and at the track. Everybody has worked very hard to get us to this point.”