A look at the history of Formula 1 title defences - the successes, the flops, and those who never returned.
Winning the Formula 1 World Championship is every young racing driver’s dream. It is the culmination of years of hard work, sacrifice and dedication - as well as a fair portion of luck.
But once the ultimate goal has been achieved and the celebrations have died down, attention quickly turns to the next challenge - defending their hard-earned title the following year. Throughout the sport’s history, world champions have experienced a wide variety of fortunes. From more success to utter disaster, carrying the number 1 on your car has been a mixed blessing.
Clearly, the best way to follow up a title-winning year is with another world championship. Nine drivers have achieved this to date, totalling 17 successful title defences between them. Alberto Ascari became the first when he won the 1952 and '53 titles back to back. The great Juan-Manuel Fangio then won four on the bounce between 1954 and '57, successfully defending his title on three occasions. Sir Jack Brabham became the third man to achieve the feat, taking the title in 1959 and defending it in '60.
It happened twice more in the nineties: first with Michael Schumacher (1994/95) and then Mika Hakkinen (1998/99). Schumacher subsequently established a new benchmark for title-defending success, winning five championships without reply between 2000 and 2004 - four successful defences. Fernando Alonso did the double in 2005/06, while Sebastian Vettel equalled Fangio's three defences by winning four successive world titles between 2010 and '13.
In fact, the most common result for a reigning world champion is to win another title. Of course, this should come as no surprise. To take the title in the first place a driver needs an excellent combination of team and car; having secured one championship, these elements tend to remain stable and provide the perfect basis for more glory. In other words, success breeds success.
This is further backed up by the fact that a runner-up finish is the second most common finishing place for a reigning world champion. It has occurred nine times between eight drivers, with Emerson Fittipaldi following up both of his title-winning years (1972 and '74) with second in the standings.
However, while a successful defence is common, not every reigning world champion has enjoyed good results. Of those who have returned to defend their crown, seven have failed to finish among the top 10 of the drivers' standings the following year.
Early examples are not wholly representative. Ascari finished 25th in 1954, but the Italian only contested two races before losing his life testing a Ferrari 750 sportscar. Meanwhile Fangio was 14th in 1958 but only contested three rounds, albeit of his own choice.
The first man to suffer through a disastrous defence in full was Brabham. The Australian had won back-to-back titles in 1959 and '60, but his 1961 campaign fell a long way short of that standard. The Australian was beset by reliability issues, finishing only two races - both of them in the points - on his way to 11th in the standings.
In 1979 the great Mario Andretti suffered a fraught title defence as his Lotus team struggled with their new car. Andretti scored just one podium and ended the season 12th in the standings.
However the man who won that year’s title, Ferrari’s Jody Scheckter, suffered an even worse defence. Scheckter opened the 1980 season with three successive DNFs, all of them caused by his Ferrari's Flat-12 engine, and scored just one points-paying finish all term. He even failed to qualify for the Canadian Grand Prix, eventually ending the season a lowly 19th in the standings.
Since then Nelson Piquet (in 1982) and Damon Hill (1997) have both finished outside the top-10 after winning the title. More recently things have been better: since the turn of the Millennium, no reigning champion has ever finished outside the top-five the following season, though Vettel could yet slip to sixth this term.
Not everyone fights to retain their F1 crown, be it by choice or (sometimes tragic) circumstances, with a total of six world titles going undefended. In the early years, 1951 champion Fangio was ruled of the following campaign after suffering injuries in a pre-season testing crash, while Mike Hawthron had retired from the sport after claiming the 1958 title, only to lose his life in a road accident a few months later. In another tragic case, 1970 champion Jochen Rindt died during his title-winning season and remains the sport's only posthumous champion.
1973 world champion Jackie Stewart became the first driver who could have defended his title who elected not to do so. Stewart quit at the season's end, with the prevalence of death in the sport playing a key part, particularly the loss of his team-mate and protege Francois Cevert.
It would be nearly 20 year before 1992 world champion Nigel Mansell decided not to defend his title, instead moving to IndyCar and winning the American series at the first attempt. Mansell's decision to quit was influenced by the arrival of Prost at the Williams team. The Frenchman went on to win the title in 1993, then retired himself. More than two decades on, Prost remains the most recent title winner not to defend his crown.
However, poor form and non-defences are the exception. The notion that success breeds success is very much true in Formula 1, particularly when it comes to world champions. That should act as further motivation to current title-chasers Lewis Hamilton and Nico Rosberg - if they needed any more incentive to chase the biggest prize in world motorsport.