The key moments of Vettel's year

It has only taken Sebastian Vettel 16 out of 19 races to clinch his fourth consecutive world championship.

But while recent grands prix have been a case of relatively plain sailing for the German, he has had to work hard for his supremacy.

Here are six key factors in Vettel's march to victory, starting way back in April at the Malaysian Grand Prix.

"MULTI 21 SEB... MULTI 21"

The seven points Sebastian Vettel gained by overtaking team-mate Mark Webber to win the Malaysian Grand Prix made no difference in the final reckoning.

The Sepang spoils ended up being just another win in a successful season. But riding roughshod over team orders proved the defining moment of an otherwise glorious campaign.

He's far from the first driver to disregard a team order - Webber himself has done similar things in the past. And you could certainly understand where Vettel was coming from when, speaking in China, he pointed out that "I never had support from his [Webber's] side".

The tension was evident in the Red Bull camp after Malaysia © XPB

But this is a team sport and disregarding a direct instruction (multi 21 referring to the order - car #2 then car #1 - that is to be maintained) was a serious misjudgement.

Considering the amount of negative stories that are spread about Vettel - the vast majority spurious - this will forever be used by the naysayers as the rope by which he is unfairly hanged even though, that day at Sepang, he was categorically in the wrong.

While not especially relevant in his march to the title, even though this was the race when he assumed a points lead he would never lose, Malaysia 2013 will loom large on Vettel's CV for all time.

ALONSO'S EARLY TROUBLES

In 2012, Fernando Alonso opened up a big championship lead through a combination of tremendous consistency and opportunism in the first half of the year.

This season, the pattern could have been similar as Red Bull's performances ebbed and flowed thanks to the Pirelli rubber in the first half of the campaign. At the very least, Alonso could have kept the fight mathematically alive for a race or two longer without three mistakes - one his own, two thanks to the team.

In Malaysia, Alonso tapped the back of Vettel's car at the second corner on the first lap. It was a small mistake, but proved very costly. With the field starting on intermediate rubber and the track only a few laps from being ready for slicks, Ferrari decided to leave Alonso out with his front wing far from secure.

As Alonso pulled out of Webber's slipstream at the start of the second lap, the front wing collapsed and put the Spaniard into the gravel and out of the race.

Alonso suffered his first DNF at Sepang © XPB

After winning in China, Ferrari made another mistake in Bahrain. When the DRS mechanism stuck open during the race, Alonso pitted and in a few seconds the team closed the rear wing. To nobody's great surprise, having been told he could use the DRS again, exactly the same thing happened and he had to return to the pits.

Alonso salvaged four points, but without the initial failure and then the decision to let the DRS be activated again, the points loss would have been significantly mitigated.

It would not have changed the end result, but perhaps it would have made things less fraught at Ferrari.

PASSING ROSBERG IN BAHRAIN

Sebastian Vettel started the Bahrain GP second on the grid knowing that overtaking pole position starter Nico Rosberg was the key to victory.

He could not pull it off at the start, but aware that Rosberg would struggle with rear tyre degradation, Vettel knew it was only a matter of time. He pulled off the pass on lap four, ensuring that he did not come under threat from the chasing Alonso.

While the Ferrari driver soon dropped out of contention, it's another example of Vettel ensuring he clears a slower car when he needs to, a quality that has proved essential in his success this year given the Red Bull's often weak top speed.

SILVERSTONE TYREAGEDDON

Red Bull had pushed hard for changes to the Pirelli tyres during the early stages of the season to no avail. Then, fate intervened and forced the Italian manufacturer to make a change for safety reasons.

A series of blow-outs at Silverstone, particularly Lewis Hamilton's dramatic failure while leading, adorned countless front pages and Pirelli knew it had to act.

After an interim solution was used at the German GP, the 'new' tyres - essentially the 2013 compound harnessed to the 2012 construction with a Kevlar rather than steel belt - were introduced in Hungary.

Vettel survived the tyre dramas at Silverstone © XPB

While Vettel managed only third there, the tyre change clearly helped Red Bull both in terms of tyre longevity and aerodynamics.

Has a race in which a title contender retired from the lead ever been so crucial in their path to the title?

HOME LAUNCH

Vettel worked hard to downplay the idea that he was at all concerned about his home 'jinx', with the German GP one of the few events he came into the season yet to have won.

But it did matter to him and when he qualified second, it was clear he was going to have to work if he was to claim victory at the Nurburgring.

Both he and team-mate Mark Webber got good launches from second and third on the grid respectively, swamping pole position man Lewis Hamilton. While Webber attacked on the outside, Vettel had the inside line and the decisive lead in the race.

PASSING HAMILTON AT SPA

Heading into the August break, Mercedes was the form team with three wins in five races. Hamilton appeared the best placed to challenge Vettel's championship lead and was many people's favourite for the Belgian GP.

While Mercedes didn't look stunning in practice, Hamilton pulled off a wonderful pole position lap in tricky conditions. He held the lead off the start, but Vettel was close.

Vettel flew to win at Spa © XPB

While the Red Bull wasn't ranked highly in the speed trap at the end of sector one, shortly before Les Combes, Vettel was stunningly fast in the main speed trap at the Raidillon. He had a good run through Eau Rouge on the first lap, got into Hamilton's tow and passed the Mercedes for the lead.

In all probability, Vettel would have won anyway such was his pace, but this was a typical example of the German making his life so much easier by executing a passing move when it really mattered.

Symbolically, the wind had been taken out of Hamilton's sails and Vettel never looked back in the championship.

It was the start of a run of six consecutive victories that ensured his rivals could not get near him in the points.