The 2009 world champion has endured a frustrating campaign so far and he struggled to a ninth-placed finish at the Australian Grand Prix on the opening weekend.
However, only a pit error cost the Brit a potential podium place at the Malaysian Grand Prix, and Button believes that the turnaround in form proves that he can be a contender this year.
"The championship is still on as far as I am concerned and I am aiming for that. Definitely," Button told The Mirror. "Sebastian [Vettel] almost beat me to the title in 2009 and he didn't score for the first four races.
"It's a massive turnaround for us. Most of the race in Sepang we were quicker than the Lotus. Most of the race we were quicker than Ferrari. Who would have thought that five days before? We are still not where we want to be and we got a bit lucky with the circuit being so smooth which helped a bit but a lot is understanding where the downforce is.
"The car is still not perfected, it was really thrown together for Sepang. The great thing is there are so many cars that are competitive and taking points off each other, which is exactly what we need."
The Chinese Grand Prix takes place on March 14.