File picture: Darron Cummings / AP Photo.

Abu Dhabi - Ferrari's Sebastian Vettel may have denied Mercedes a one-two finish as in the past three Formula One season standings, but the finale in Abu Dhabi showed that he faces a tough road in his bid to make it right to the top.

Mercedes handily won Sunday's race from Valtteri Bottas and world champion Lewis Hamilton, with Vettel trailing by some 19 seconds in third place.

The German had initially hoped to add a final win in Abu Dhabi to that from Brazil a fortnight ago to boost his morale and lay down a marker.

Instead, it is Mercedes that heads into the off-season with plenty of confidence, even though Vettel at least finished second overall behind Hamilton and ahead of Bottas.

"Mercedes has been more consistent," Vettel admitted, as he and Ferrari suffered several setbacks in the second half of the season after dominating the first half.

Hamilton struck a similar line when he praised Mercedes' reliability after becoming only the third driver (the others being Michael Schumacher and Juan Manuel Fangio) to score points in every season race en route to a world title.

"When teams are pushing right to the limit, you're pushing, you're squeezing every drop from the car, yet you've got to make it go quite a long distance in terms of life and reliability. I think that's really where the stamina of Ferrari was not the same as Mercedes," the Briton said.

While voicing disappointment that he lost the title duel with two races to spare, Vettel nonetheless pointed out that Ferrari has come a long way since some very modest seasons by the team's standard.

But he also admitted it is also a very long way to the top the Scuderia last occupied from Kimi Raikkonen in 2007.

"It's against the spirit of Ferrari to give up. I am sure we have a lot of things to improve and the people are very motivated. So, I am looking forward to next season," he said.

Vettel and Hamilton will each enter the 2018 campaign as four-time champions - renewing their duel over 21 races from the March 25 opener in Australia to the November 25 finale in Abu Dhabi.

But the work already starts on Tuesday when they are engaged in some testing in Abu Dhabi for the next season, and a true holiday won't start until shortly before Christmas for the stars who also have other team and sponsor commitments.

"It's just crazy, Formula One just doesn't sleep, it just keeps going, keeps moving on," Hamilton said.

Drivers will have to get used to some changes next year, most notably the halo cockpit protection device.

The number of power units per car has been cut from four to three over the season while Pirelli has announced to have seven instead of five different tyres available for the season.

In addition, Formula One's new owners unveiled a new logo for the series shortly after Sunday's finale - which left the top drivers rather unimpressed.

"I think the one that we already had was an iconic logo. Just imagine Ferrari changing their logo, or Mercedes changed their logo," Hamilton said. "I don't think the new one is as iconic but maybe it will grow on us."