Bagnaia and works Ducati team-mate Jack Miller were the only two drivers to use the hard front in the cold Sunday race at Misano, with the latter falling out on lap four.
Bagnaia led the race for the first 22 of 27 laps, got his pick right and defied pressure from eventual race winner Marc Marquez and was on track to keep his title hopes alive as Fabio Quartararo only finished fourth.
But Bagnaia crashed on lap 23 when he lost the front of his Ducati through Turn 15 to the left, just as Miller did earlier in the race, handing the title over to Quartararo.
Rossi has previously spoken about trying to influence Bagnaia’s tire choice in races, believing the Ducati rider should have driven the middle front instead – although Bagnaia later admitted he wasn’t comfortable on that compound.
“Pecco has had a fantastic season,” said Rossi.
“I’m a little mad at him today because I think he could win if he started at the middle front because he was the fastest.
“But I think so. He had a great chance of keeping the championship open.
“It was difficult anyway, but it was important to bring it to Portugal. But it is so, but I think Pecco, Franco [Morbidelli], also Luca [Marini] will be very strong next year. “
Valentino Rossi, Petronas Yamaha SR, Luca Marini, Esponsorama Racing
Photo by: MotoGP
Rossi made his last MotoGP appearance on home soil on Sunday and came through last on the grid to only achieve his third top 10 result in 2021 in 10th place.
The nine-time Grand Prix World Champion considered this the “best way to say ciao to your home fans”.
“I’m happy about today because I drove a decent pace,” added Rossi.
“I am very happy, that’s the best way to say ciao. I didn’t want to go into a bad race and be left behind so I’ve tried to stay focused and it’s always difficult to start from behind.
“But I felt good with the bike and the tires, I know that my potential is better when it’s completely dry.
“I was able to do a few overtaking maneuvers, fight a few fights right up to the last lap, and in the end I made it into the top 10.
“So it’s the best way to say ciao to the audience because there was a fantastic atmosphere around the track.
“There were a lot of fans, it was a sunny day, so I’m happy. It was good, it was very, very emotional. “