Yamaha must not think it has solved its MotoGP problems after its most competitive showing for many races in Thailand, warns Valentino Rossi.
After an insipid showing in Aragon, where Rossi was eighth and factory team-mate Maverick Vinales trailed home in 10th, both the works Yamaha racers enjoyed much more competitive outings at the new Buriram track last weekend.
Rossi qualified second and finished fourth, one place behind Vinales, who secured the manufacturer's first top-three result since July's Sachsenring round prior to the summer break.
But Rossi said Yamaha cannot be satisfied with one good race and must consider it within the context of a sub-par latter half of the campaign.
"This is unfortunately a risk [that Yamaha thinks it has solved its problems], but it is a losing mentality," he said.
"So many times our engineers are happy if Maverick can make a good time in testing, they say, 'we got it!'
"If I were a Yamaha engineer, I would analyse the results of the second part of the season and I would not be happy about one fast lap or a front row."
Rossi admitted Yamaha's strong form was unexpected, saying he felt the grip of the Buriram track surface could have contributed to the team's strong performance.
"On paper this is not a Yamaha track," said the Italian.
"I expected to suffer a lot more and to be for example stronger in Misano, but in Misano we struggled.
"For me, more than the layout of the track, the different grip of the asphalt helped us, more or less.
"If you want to be competitive you have to be strong everywhere because now Ducati and Honda are strong everywhere.
"For me, we [are] missing something but maybe this weekend we improved, we will see in Motegi."
Rossi enjoyed a spell in the lead of the Buriram race, passing Marquez on lap five, but slipped back to third six laps later and stayed there until he was passed by Vinales in the latter stages.
The seven-time premier class champion said he had no answer for his team-mate's late-race pace and conceded the Spaniard did the better job.
He recalled: "I try for all the race to save the tyres like everybody, because it's more [like a] cycling race now - everybody waiting, sometimes one pushes for two laps, [then] all the other guys follow but after slow down.
"But in the last laps I was more in trouble, and I missed this two or three tenths.
"During the weekend he [Vinales] followed another direction in the setting and is able to ride that type of bike and maybe save the tyre in a better way."