The Yamaha rider qualified as the top non-Ducati rider in sixth at the Circuit of Americas and displayed strong race pace throughout practice.
However, Quartararo was unable to mount a challenge for the podium and took the chequered flag in seventh after a late battle with Honda's Marc Marquez.
The Frenchman sits fifth in the standings 17 points adrift of Americas GP winner Enea Bastianini having so far scored just one podium in his title defence.
When asked by Motorsport.com if he is confident the 2022 Yamaha is a bike he can fight for the championship with, Quartararo said: "To be honest, when we are on this kind of track we are not ready to fight for the podium.
"But now we are going to Europe, better tracks – I think – for us and I'm just going to do my best to fight for the championship.
"Then, if the bike is ready? I have my opinion, but I give all the time my 100% - like today. For sixth position or seventh, I give my 100% all the time."
Motorsport.com did press Quartararo to reveal his opinion on the Yamaha, but he replied: "I will keep it for myself."
Quartararo says he struggled early on at COTA with a lack of grip just as he did in Argentina, though the problem wasn't as severe.
"I mean in the beginning of the race it's a little bit same problem as Argentina but much less, that basically we missed that initial grip compared to the others," he added.
"But I think I managed OK, I was able to defend quite OK and in the beginning it was more difficult because everyone is more tight and the straight is unfortunately we were losing quite a lot.
"But I think we made a really good race, I enjoyed a lot, we battled really hard even if it was for sixth position.
"I enjoyed the battle with Marc. Just even if we are struggling, for me I learned more from this kind of race than some races that I've won.
"Today I learned a lot and I'm happy because even if I have less power, I pushed myself to the limit. So the day I have the power I will have much better result."
The next two races take place at Portimao and Jerez – venues Quartararo was strong at in 2021 – but feels the former will be "50/50" for Yamaha.
"I will say Portimao is good, not the best," he said when asked if he thought the Portugal/Spain back-to-back would be better for Yamaha.
"Depends a lot there. If you start first and make your pace it's great, but later in the year last year I was stuck behind Ducatis and I couldn't overtake.
"But if you go away or are in the top three, you can manage to get a good result. So, this [Portimao] is 50/50 and Jerez will be a good track for us."
