Malaysian Grand Prix race winner Lewis Hamilton says he is wary that rivals Red Bull has a 'good car'.
Hamilton led home team-mate Nico Rosberg as Mercedes moved 53 points clear of Red Bull in the constructors' championship as he labelled the W05 'probably the best car I have ever driven'.
But the Brit is aware that despite Mercedes closing the gap to Red Bull in terms of downforce, they have to keep pushing to remain ahead of their rivals as Sebastian Vettel completed the top three at Sepang.
"The development has to continue," said Hamilton. "Red Bull clearly have a very good car, but development is a normal thing in Formula 1. And all things are not completely new - even if there is a saying that this year is a totally new ballgame.
"Take for example the front wing: it’s a modified spec of last year’s and that means that they [Red Bull] are going to have a good car. But I think we have closed the gap in that respect compared to last year - and now we just have to keep going."
Hamilton believes that his year of experience with Mercedes has aided his progress with this season's car.
"I was working so much harder than in the past, and of course it helped that I had one year with the team under my belt to know how we best work together - and what I can pull from every individual to achieve the maximum," he said.
"What is - and was - the most important thing is that I feel really comfortable in this car. Remember, last season I sometimes said that I felt uncomfortable in the car - but that is all history. Considering that I had one win and some good results in 2013 in a car that didn’t suit me perfectly, I am very much looking forward to how this season progresses."