Formula 1 will stage its final race of the 2019 season - and last event of the decade - in Abu Dhabi this weekend.
The first season to finish in December since 1963, Sunday's race marks the end of a 21-race campaign which began in March and has seen Mercedes win a record-setting sixth consecutive world championship double.
But the season is finishing with arguably its most competitive and unpredictable series of races since the Mercedes era began five years ago.
In the eight races since August's summer break, F1's world champions have only qualified on pole position once, with world champion Lewis Hamilton winning two of those grands prix and Mercedes half.
Red Bull's Max Verstappen, meanwhile, triumphed in a thrilling race last time out in Brazil, where Ferrari team-mates Sebastian Vettel and Charles Leclerc clashed on track to heighten focus on their in-house battle for supremacy.
For Hamilton, hoping to end his sixth title-winning year with an 11th victory of 2019, the increased competition is welcome news.
"The Honda's obviously made some big steps and it's great to see another manufacturer as strong as they are now," said the Mercedes driver.
"It means that hopefully next year we're going to have a serious three-way, four-way battle and that's great for Formula 1."
What's still up for grabs?
Although neither world championship is on the line at this year's season finale, there are still some interesting championship sub-plots to play out…
Verstappen or Leclerc for third?
The two leading stars of F1's new young generation, two of the drivers of the season, and now in a direct battle for third in the Drivers' Championship. Verstappen's brilliant Interlagos victory, coupled with Leclerc's retirement, means the Red Bull driver is the strong favourite to finish as the first non-Mercedes driver in this year's championship. Verstappen holds an 11-point advantage over Leclerc.
Leclerc or Vettel as lead Ferrari driver?
He may not be able to finish third overall, but Sebastian Vettel still has an outside chance to overhauling Leclerc to end the year as the Ferrari driver with the most points. But it's a tall order for the former world champion: Leclerc leads him by 19 points and so Vettel, who has only previously been outscored by a team-mate over an F1 season by Daniel Ricciardo back in 2014, must either win the race or finish second with the fastest lap to have any chance of avoiding a repeat.
Can Sainz claim two Red Bull scalps?
Given Pierre Gasly and Alex Albon have each spent half a season apiece at race-winning Red Bull, McLaren's Carlos Sainz chance of beating both to sixth in the drivers' standings is noteworthy. Gasly and Sainz are tied on 95 points - with the Frenchman holding sixth on countback after his sensational second at Interlagos - with current Red Bull incumbent Albon 11 back after the unfortunate end to his Brazil.
Renault to hold on to sixth from Toro Rosso?
Having already fallen short of their pre-season targets, with fourth confirmed by resurgent McLaren in Brazil, Renault will hope to at least hang on to fifth place in the Constructors' Championship in Abu Dhabi. They hold an eight-point advantage over Toro Rosso, who have only once finished in the top-six of the teams' standings before.
The last race of the 2019 F1 season takes place in Abu Dhabi on December 1, and will be exclusively live on Sky Sports F1.