London - Formula One entered a new era in 2017 and next year promises another first even if Mercedes and Lewis Hamilton keep on winning.
Hamilton's fourth title, in the sport's first season under new US-based owner Liberty Media after the Bernie Ecclestone decades, has set the scene for an unprecedented battle on the track in 2018.
Never before have two quadruple world champions fought each other for a fifth crown but Hamilton and Ferrari's Sebastian Vettel will be lining up to do just that come the Australian season-opener on 25 March 25.
How they shape up will be fascinating to watch, with Hamilton staying remarkably cool and composed in 2017 while Vettel let the rising pressure get to him and occasionally blew his top.
Hamilton rewrote significant chunks of the record books in 2017, overtaking Jackie Stewart to become Britain's most successful driver of all time and first to take four titles.
Championship double
He took his tally of wins to 62, more than anyone other than retired seven-times world champion Michael Schumacher (91), and eclipsed Schumacher's all-time record of pole positions to end the season with 72.
Hamilton scored points in every race, winning nine out of 20, while Vettel, the overall runner-up after leading until September, took five as his challenge faded amid collisions and mechanical failures.
Mercedes completed the championship double for the fourth consecutive year, despite rule changes that made the cars faster and wider on fatter tyres.
Ferrari, whose last driver's championship was with Kimi Raikkonen in 2007, aims to be stronger in 2018, when there will be one more race and the engine quota is reduced from four to three per driver.
"I can't expect him to make the same mistakes," said Hamilton before collecting his winner's trophy. "I've got to make sure I'm even better next year to stay ahead of him."
McLaren revival?
With Vettel's team mate Raikkonen nearing the end of his career and Valtteri Bottas some way off Hamilton at Mercedes, Renault must also raise its game if others are to enter the title reckoning.
Renault now has former champion McLaren on the list of engine customers after that team's tortured relationship with Honda finally ended. Fernando Alonso, a double world champion who missed Monaco in May to try and win the Indianapolis 500, can hope to be back on the podium for the first time since 2014 when he was at Ferrari.
Honda, which could at least celebrate Takuma Sato becoming the first Japanese to win the Indy 500, will now focus on Red Bull-owned Toro Rosso.
Red Bull won three races with Renault engines, with Dutch 20-year-old Max Verstappen and Australian Daniel Ricciardo increasingly taking the fight to Mercedes and Ferrari. One of those victories proved a highlight of the season, with Ricciardo triumphant in Azerbaijan in a cracker of a race.
It was also a low point for Vettel, who collided with Hamilton behind the safety car in an incident of 'road rage'.
"The worst feeling I had was after Baku I think," Vettel said later, "just because I sort of ruined the race with something unnecessary, so I struggled with that."
Big battles looming
Hamilton won the title in Mexico but singled out winning at Silverstone as a highlight because of the support he received from the home fans after the 'negativity' surrounding his absence from an earlier London event.
That free demonstration was part of Liberty's plans to bring the sport closer to fans and raise the profile. The jury remains out on their efforts, with teams concerned about a drop in revenues in 2018 as a result of the increased spending.
There are also some big battles looming over the sport's direction, with Ferrari warning it could walk away after contracts expire in 2020 if doesn't like what is being offered.
Those who left the scene in 2017, apart from 87-year-old Ecclestone who was handed an emeritus title and attended only a handful of races, included retiring Brazilian Felipe Massa and Britain's Jolyon Palmer.
The Malaysian Grand Prix also bowed out but France will return next season for the first time since 2008, as part of an unprecedented triple header with Austria and Britain, while Germany will also be back after a year's absence.