They think it's all over - but is Nico Rosberg's grip on the 2016 F1 world title as firm as it seems?

Nico Rosberg leads his Mercedes Formula 1 teammate Lewis Hamilton by 33 points after he won the Japanese Grand Prix last weekend while his title rival finished third. There are a maximum of 100 points available from the four remaining races.

But can it still slip away from Rosberg's grasp? We've dug out some memorable moments from recent F1 history where the driver in Rosberg's position has not managed to hold on, as food for thought.

Since the 2000 season, the driver leading the championship with four races to go has claimed the crown in 13 out of 16 years, and only three times has a points deficit been turned around into a triumph.

So is Rosberg’s maiden world championship victory – and his first title since he won the inaugural GP2 championship in 2005 – a foregone conclusion?

The German driver can now afford to finish second to Hamilton at all of the remaining races in the 2016 season and still claim the crown, but that scenario is not very likely as Mercedes has only managed four one-two finishes all season, a third as many as last year. As was proved in the recent Malaysian Grand Prix, unexpected reliability problems could also yet hurt either Mercedes driver.

As we outlined here, both Hamilton and Rosberg have been hit with mechanical troubles during the 2016 season, but the Briton’s issues have certainly come at worse times.

Race starts are another big variable which has hurt Mercedes this year; Mercedes has admitted that its clutch system is difficult for its drivers to use and causes problems during race starts. "The clutch we are giving them is not perfect," said the company’s motorsport boss Toto Wolff after Hamilton lost six positions on the run to Turn 1 after a slow getaway in Japan. “It is difficult to handle the clutch in the right way.”

Hamilton appears to be having more issues with this than his teammate, but Rosberg has lost out to faster starting cars on several occasions this year too.

As has been the case in the last two years of Mercedes’ F1 dominance, if its cars are not running in clean air they struggle to get back past their competitors. This was evidenced by both Rosberg and Hamilton each finishing third in the last two races after losing places at the start (the former was spun around by Ferrari’s Sebastian Vettel in Malaysia).

The clutch issue could also trigger a further potential problem for Rosberg – other teams taking points away from him. This year, the third season in a row that it has won the constructors' championship, Mercedes has only scored four 1-2 finishes compared to the 12 it scored in 2015 and 11 in 2014, which is in part down to the improvements made by its rivals Red Bull and Ferrari.

If a start issue costs Rosberg places to those teams that he could not fully recover over the course of a race – as Hamilton could not in Japan – he can only afford to finish third once (assuming Hamilton wins all of the remaining races) and come second at the other three races and still win the title.

While those are all hypothetical scenarios, there are several instances in F1 history of drivers overturning large points gaps and winning the championship.

Christian Horner, boss the Red Bull team who saw Sebastian Vettel win the 2010 title despite being third in the championship entering the final race (see below), believes that Hamilton should not give up in his quest to beat Rosberg to the 2016 championship.

"He only needs that sniff of something,” said Horner. “A DNF from Nico and a win from Lewis and he's right back in the game again, so things can change very quickly.

"We saw it with Kimi [Raikkonen] when he stole the championship from under the noses of Lewis and Fernando [Alonso] in 2007. There are still 100 points available in this championship and it would be a foolish person to rule him out at this stage."

With all of that in mind, here are five memorable occasions the world championship was won by drivers fighting back from behind in the closing stages of the season.

2007 – Kimi Raikkonen

Despite going into the final two races of his first season as a Ferrari driver 17 points behind the McLaren pair of Alonso and Hamilton, (with a maximum of 10pts available for a win) Raikkonen remarkably took the title with two crucial victories as his rivals faltered.

Alonso lost valuable ground by crashing at the Japanese Grand Prix, but it was Hamilton’s worn tyre wear induced DNF and gearbox problems at the Chinese and Brazilian races that left Raikkonen with a slim chance to win, which he went on to do by just one point.

1976 – James Hunt

The 1976 season and the title battle between James Hunt and Niki Lauda, immortalised in the 2013 film Rush, went down to the wire after the Briton closed the points gap to the Ferrari driver who missed two races as a result of his enormous accident at the Nurburgring.

Lauda came back quickly despite his injuries – he sensationally finished fourth at the Italian Grand Prix just six weeks after the crash – but he pulled out of the finale in Fuji due to the torrential conditions while Hunt finished third to take the title by a single point.

2000 – Michael Schumacher

Schumacher won his first title for Ferrari – and the Scuderia’s first since 1979 – by overturning a deficit to McLaren’s Mika Hakkinen in the final four races of the 2000 season.

The German driver took three consecutive victories to win his third world title with a race to spare (which he also went on to win) as an engine failure at Indianapolis cost Hakkinen dearly.

1986 – Alain Prost

Prost’s second title bears similarities to Raikkonen’s triumph in 2007 as he beat two bitterly battling teammates to take an unlikely crown.

The Frenchman was 11 points adrift of Nigel Mansell and one behind Nelson Piquet in the second Williams (in the days when a win was worth 9 points) with two races to go, but a second place finish at the penultimate round in Mexico and then a victory in Australia after Mansell’s tyre exploded (the Briton was running in the third place he needed to secure the title) was enough to claim the championship by just two points.

2010 – Sebastian Vettel

Four drivers – Vettel, Alonso, Mark Webber and Hamilton – arrived at the season finale in Abu Dhabi in mathematical contention for the 2010 title.

Alonso and Webber were separated by just eight points, with Vettel 15 behind the Spaniard and Hamilton nine further adrift and with a very outside shot of winning the championship.

Ferrari concentrated on covering Webber’s race strategy – a grave error as Vettel won the race while Alonso and Webber got stuck in the pack down in seventh and eighth, famously behind Vitaly Petrov’s Renault. The result was enough to give Vettel his first world championship by four points over Alonso.