Valentino Rossi's hopes of a top-six Aragon finish ended after less than a lap on Sunday, when the Ducati star tangled with Jonathan Rea under braking for the final turn.
Rossi came close to clipping the Ulsterman ahead of him, before running straight on and re-joining in 21st and last place.
The Italian, runner-up at the previous Misano round, then worked his way back up to eighth by the chequered flag. In the process, Rossi set the eighth fastest lap of the race, 1.6s slower than winner Dani Pedrosa (Honda).
“It's a shame about the mistake on the first lap,” said Rossi. “I was a bit faster than Rea, and when we spread out on the straightaway, and he braked a bit earlier, I went to the right. He couldn't see me and pushed me close to the curb, and I went straight to avoid him. I would have had to go to the inside, not the outside.
“Without that incident, I think I could have fought with Bautista for sixth place, which was our potential at this track today. In fact, things went better in the race than in practice, when we suffered a lot on acceleration both in the wet and in the dry.
“We made some changes after the warm-up, and that helped us to lap consistently at a decent pace for the whole race, without using up the tyres too much. This is a positive sign, considering that we were also able to do that at Misano.
“There's still much work to do, but it's also true that for us this was probably the most difficult track among those left on the calendar, so we hope to be more competitive at Motegi in two weeks.”
Aragon marked Rossi's second race with a new Ducati chassis and swing-arm. Team manager Vittoriano Guareschi felt that the poor practice weather hit them especially hard, but was impressed with the set-up decisions.
“With the new frame and swingarm, it's a period when we needed to ride as much as possible, but the only dry session was qualifying, when it was more important to do a good time than to try different settings,” he said.
“We had the warm-up this morning, and I must say that the team did a good job of finding solutions that allowed Vale to ride until the end at a good pace, without wearing the tyres too much.”
Rossi's team-mate Nicky Hayden suffered a dramatic accident on the second lap, but was later declared as fit for the forthcoming Japanese round.