The German driver took three wins in his first year with the Italian squad last season and set the goal of fighting for the title in 2016.

However, Vettel and his team have endured a difficult year and are already out of contention, having failed to score a race win in the first 14 rounds of the championship.

Vettel insists Ferrari is the first to be disappointed with its year, but denied the season has been a disaster.

"It's true that we didn't have a great season so far, but it's also true that it's not a bad, an awful season as some people might look at it," said Vettel on Thursday.

"We are criticising ourselves first because we haven't achieved what we set out to achieve. We were closing the gap last year and unfortunately the gap to the top is still there.

"Sometimes bigger, sometimes smaller, but it's still there. Do I have confidence that we will win races in the future? One hundred percent."

Teammate Kimi Raikkonen, meanwhile, said Ferrari has actually taken a step forward compared to last year.

"We are better than we were last year, but obviously others probably improved more, I'd have to say. We are doing right things, I'm sure, we have great people and a great atmosphere but the speed is missing a bit."

Vettel, who had won the Singapore Grand Prix four time in eight races including last year, believes the Marina Bay event offers his team a good chance to grab the first victory of 2016.

"Obviously we are aiming high. We might have a chance here, plus there's always random things that can happen here. On paper there might be some tracks that suit us more, some less, but it is always a combination of so many things.

"I'm not really looking at the different characteristics and saying 'this might be the track or this might not'. I think that's the wrong approach. I think you should always try to do your best, aim for the highest.

"In the end I'm here to win. That's what I'll try to do this weekend. It might sound optimistic but you never know what happens."

Additional reporting by Roberto Chinchero