This weekend's Japanese Grand Prix takes place at one of the most demanding circuits on the calendar — and with Fernando Alonso starting to strech out a lead it could be a pivotal point in the title race.
Alonso has climbed the championship ladder through consistency and while he has claimed three victories and five other podiums his advantage has been significantly boosted by his rivals' failings.
The Ferrari man has dropped out on just one occasion while McLaren, whose car is often the fastest on the grid, have seen a total of nine retirements across their two cars; Red Bull's drivers have each dropped out on three occasions.
For Lewis Hamilton, his mechanical failure in Singapore was a disaster. Before that race, he was second, 37 points back and tantalisingly in contention; now he is fourth, 52 points back. With just 150 points left on the board, to come back from that is a tough ask.
After his victory, Vettel is now closest to Alonso — but even if he was to win this weekend and Alonso drop out, he still would not overhaul the Spaniard, who is 29 points ahead.
Even taking in all remaining six races, it looks like a tough ask for him too. Alonso has scored an average of 14 points per race this season (including his one retirement) and if he maintains that Vettel would have to average 19 points per race (meaning he must win at least one more race) to beat him. He's currently running at an average of 12 points per race and even when taking out his retirements, that only rises to 15.
However, Suzuka could be a good place to start.
The former Honda test track is literally designed to expose the strengths and weaknesses of a car. It has demanding and different corners and above all it rewards good high speed stability. If any car has that, and has had that for years, it's the Red Bull.
Vettel has taken the last three pole positions at Suzuka, winning in 2009 and 2010 and finishing on the podium in third last year. Which is encouraging for the German, to say the least.
Most of the circuit focus is on high speed and ideally engineers would go for aerodynamics and gearing suited to higher speeds, but the need to get a stable car that can be pushed hard means significant compromise.
The Esses are where massive chunks of time can be gained or lost. They are a long sequence of inter-connected turns where one minor mistake, or a set-up that does not allow the car to attack early in this sequence, can have a massive knock-on effect.
With the use of DRS, teams will add a little more downforce without being so compromised, but the engine also plays a significant part in the drivability of the Suzuka track.
An engine that is smooth and progressive in the transitions between the turns, with smooth gearchanges, will provide a driver with a much more fluid and attacking driving approach. Teams will select gear ratios specially to put the engine in the best part of its power band during the short accelerations between each corner — so an engine with a wide power band can be a significant advantage as it reduces gear changes and maintains better balance.
The track has an abrasive track surface, so tyre wear could also be a key factor in the race — but the figure of eight layout puts stress on the right- and the left-side tyres so individual tyre stresses are not as high as would be expected at a track with such high speeds. Also, as long as no rain hits, the track evolves a lot so rubber laid down makes the circuit less aggressive on tyres by Sunday afternoon — but if it rains, that washes all away and it's back to square one.
Ferrari had a competitive car in Italy, but struggled with their new parts in Singapore — they took the new rear wing off the car and ran with the old one. They will need a significant step forward to keep Alonso at the sharp end — but that said, all he needs to do is continue to consistently clock up points for the remainder of the season, so as long as they can keep his average up they should take a cautious approach to any developments.
McLaren's car works everywhere on all kinds of corners but their car failures show they have been pushing hard. If they can cut the frailties and Alonso has a bad weekend things could turn around again — and with Hamilton 52 points behind and Jenson Button 75 points back, all the McLaren balls must surely now be in Hamilton's court.
With Vettel now 32 points ahead of team-mate Mark Webber, the same should be true at Red Bull and they have been strengthening in recent races, with a new front wing giving them another good boost in Singapore.
So it's now or never for Vettel and (less so) Hamilton - but in truth, Alonso needs to have a couple of really bad weekends for the championship to get interesting again. And with the consistency he's had this year, it's hard to see that happening.