Max Verstappen has an eight-point lead over Lewis Hamilton in the Drivers' Championship heading into the penultimate event of the season in Saudi Arabia.
The title race looks set to go down to the wire and it's simply too close to call. Verstappen has a handy points buffer, but Hamilton seems to have the better car and will be favourite to win the final two races.
One major factor behind Hamilton's pace advantage is his new Internal Combustion Engine, which was introduced at the Brazilian GP.
Hamilton took victory at Interlagos, having started from the back of the grid in Sprint Qualifying and begun the Grand Prix itself from 10th. It was a remarkable display and a performance that raised many eyebrows.
The seven-time World Champion will use that fresh engine this weekend in Saudi Arabia and at the finale in Abu Dhabi, having saved it last time out in Qatar.
Given how much performance has come from the new engine, should Red Bull be bold by fitting Verstappen's car with a fresh unit?
All in for Abu Dhabi?
The big question Red Bull have to ask themselves is how much performance they would gain from a new engine. Verstappen's last engine change came six events ago at the Russian GP.
It's not entirely known whether Verstappen has used the same engine at each of the six races, but the mileage on his unit will still be at least twice as much as Hamilton's.
Putting a precise number on the performance loss as an engine gets older is almost impossible. A more important element of modern F1 engines is how often a high power mode can be used.
In a battle for the win, such as the fight between Verstappen and Hamilton in Sao Paulo, the latter was able to put relentless pressure on the Dutchman mainly due to the way he could keep his tyres in the right window, but also with the freshness of his power unit.
A small deficit of 0.1-0.2 seconds on average per lap could make the difference in this championship if it comes down to an on-track battle.
Should Verstappen win one of the last two races, he would likely be champion, so sacrificing Saudi Arabia (by taking a five-grid place penalty) to give himself every possibility of winning in Abu Dhabi cannot be ruled out.
The argument against that is he would be putting all of his eggs in one basket to win in Abu Dhabi, rather than having two shots at victory.
However, Mercedes' recent pace advantage must be a concern for Red Bull.
Wiping out reliability worries
Verstappen's engine could be on its eighth race in Abu Dhabi, which would be unprecedented territory for Honda.
A reliability problem would almost certainly end Verstappen's title hopes, so a new engine would significantly reduce any fears.
Perhaps the bigger risk would actually be trying to push an ageing engine hard in the final two races.
Putting Verstappen in danger
A five-grid place penalty for a new Internal Combustion Engine would see Verstappen start no higher than sixth.
There will be numerous dangers on the opening lap with the walls not far away and rival cars all around - just centimetres away - in the first few corners.
Contact is the last thing Verstappen would need, and the other drivers know they can be aggressive against the Red Bull driver, since he has more to lose.
It may go the other way, though, as a chaotic race could see Verstappen in a winning position, having started in the midfield, in a similar way to the conclusion of the Russian GP, when he found himself in second place due to a late rain shower.
Very few people have even discussed the idea of Verstappen taking on a new engine. It would be a very bold move from Red Bull, but they have a reputation of going on the offensive.
A fresh Internal Combustion Engine would underline these traits, although that isn't something that appears likely for Saudi Arabia. A team spokesperson has confirmed to RacingNews365.com that there are currently no plans to change Verstappen's engine this weekend.
The best option would be to see where they are in terms of pace during Friday practice. If Red Bull are leading the way, they should have faith that they can maintain their advantage into qualifying and take pole position, which would give Verstappen the best chance of winning.
However, should Mercedes have a clear advantage, it might be best to be brave and take on a new engine. Red Bull can then hope for mayhem in the race and also have the benefit of a very fresh engine for Abu Dhabi.
Remember, Verstappen can afford to finish fifth in Saudi Arabia and still be within seven points of Hamilton, meaning it would be a winner takes all scenario at the Yas Marina finale.
It's remarkable that F1's engine and grid penalty system has played such a big role in this year's title race, and it could still produce another twist.
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