Red Bull saw some potential, and after a learning year with Toro Rosso, its faith was repaid in 2019.

Verstappen won in Austria, Germany and Brazil, and took poles in Hungary and Brazil, losing a third in Mexico to a yellow flag infringement. It was the perfect springboard for an even stronger campaign in 2020.

However, given the depth of the competition from Mercedes and Ferrari there will be no margin for error.

The new RB16 will have to be competitive on all types of tracks from the start of the season, and the Milton Keynes outfit will have to set the development pace, while at the same time pressing on with its 2021 project.

And Honda will have to raise its game another notch. Having made huge strides in 2019 it will have to at least match the opposition in terms of both pure performance and reliability. And it's the latter area where the question marks remain.

A title can be won or lost by a handful of points, and thus a power unit grid penalty here or there could make a crucial difference. It's no co-incidence that in 2019 world champion Lewis Hamilton made it to the end of the season with a "perfect score" of usage, and thus no associated grid penalties.

Max Verstappen, Red Bull Racing RB15, leads Lewis Hamilton, Mercedes AMG F1 W10 Photo by: Mark Sutton / Motorsport Images

He completed the 21 race weekends having used the prescribed limit of three V6s, turbos and MGU-Hs, and two MGU-Ks, control electronic units and energy stores. Hamilton's Mercedes team mate Valtteri Bottas was less fortunate, taking a back of the grid hit at the Abu Dhabi finale.

Rivals Ferrari weren't too far off a perfect run – Charles Leclerc required a fourth V6, while Sebastian Vettel used an extra CE, both men escaping with five-place penalties.

In contrast both Verstappen and the sister Red Bull entry shared by Pierre Gasly and Alex Albon were into the penalty zone with all six elements – and both cars used two more V6s than the rules allow for.

The totals at the other Honda-powered team, Toro Rosso, were even higher – both STR14s ran seven V6s, or four more than specified in the regs.

Nevertheless the numbers from Honda's five years in the sport since the first hybrid season with McLaren indicate a positive trend in terms of usage, one that Red Bull can only hope continues into 2020.

Here's a summary of how its teams have fared since 2015:

Driver/year ICE Turbo MGU-H MGU-K ES CE Alonso/Magnussen (2015 - 19 races) 12 11 11 8 4 7 Button 11 12 12 10 4 6 Alonso/Vandoorne (2016 - 21 races) 8 9 9 7 7 7 Button 6 6 6 6 6 6 Alonso (2017 - 20 races) 9 11 11 8 7 6 Vandoorne 10 12 12 9 7 7 Hartley (2018 - 21 races) 8 8 8 7 3 4 Gasly 8 8 8 6 3 3 Kvyat (2019 - 21 races) 7 7 7 6 3 3 Albon/Gasly 7 5 5 5 3 3 Verstappen 5 4 4 3 3 3 Gasly/Albon 5 5 5 4 3 3

The numbers don't tell the full story. Pure reliability is not the only factor in determining how teams and their engine partners deploy power unit elements over a season – often it's not just about simply replacing failed components.

Sometimes a driver is well down the grid or at the back for other reasons, and thus taking new elements and putting them into the pool carries no extra penalty. Indeed until the rules were tightened teams sometimes took more than one extra set over a weekend, as it made no difference.

In addition there are tactical changes related to taking a hit so that fresh examples of a new spec can be available for power sensitive tracks like Spa or Monza. Sometimes an update is fitted in a car simply to assess it and put mileage on it – and if you are not chasing the title, you can take a penalty hit without too much regret.

Max Verstappen, Red Bull Racing RB15 Photo by: Glenn Dunbar / Motorsport Images

Then there's the key factor of the overall mileage strategy, and the difficult balance between performance and how far you dare to run at that level. Mercedes did it by the book in 2019, and Hamilton's three power units completed an average of seven full race weekends apiece.

Honda in contrast went into the season with a more conservative target – it knew that its engines could not manage seven weekends at the required level of performance, and that new units and penalties would have to be factored in.

Honda's power unit usage numbers have been impacted by all the above factors over the past five years. However, even allowing for extra usage by McLaren and Toro Rosso when there was little to lose by changing elements, the general trend is clear.

If one takes the V6 as the key benchmark, the McLaren drivers used 12 and 11 examples respectively in 2015, eight and six in 2016, and 10 and nine in 2017. In 2018, when Honda's reliability was better but experimenting with specs played a role in some changes, the two Toro Rossos used eight apiece.

With those figures in mind the fact that the two Red Bulls needed "only" five V6s each to get through 2019 was a significant step. However, taking the new elements was expensive, and cost Verstappen points that he can ill-afford to sacrifice in 2020.

Honda introduced its Spec 4 engine on Friday of the Belgian GP in both the Red Bull of Albon and the Toro Rosso of Daniil Kvyat, sending both men to the back of the grid for that race.

For obvious reasons local favourite Verstappen was kept free of penalties at Spa, although ultimately the tactic didn't help him as he was a first lap retirement.

Instead he took the full set of new Spec 4 components at Monza, where he started from the back. In a race of relatively low attrition he could only recover to eighth.

Just two events later in Russia Verstappen took another new V6 for the pool, his fifth of the year. Again, the timing was influenced by the PR factor – Honda didn't want to take any chances with its star driver heading to its home race at Suzuka – and this five-place hit for one element change was regarded as a worth taking.

Max Verstappen, Red Bull Racing RB15 Photo by: Zak Mauger / Motorsport Images

Verstappen qualified fourth in Sochi, and thus started ninth. In the race he managed to recover to fourth, but again points were lost – and Bottas, who qualified behind him, finished second.

In the grand scheme of things it didn't matter too much, as Verstappen was never really in the title fight. It was all about individual results, and proving that the Red Bull-Honda combination could win races.

That can't be the case in 2020, as the team has to target the championship. A record 22-race calendar makes it a tougher challenge than before, although an extra allowance of a third MGU-K has given all the manufacturers a bit of wiggle room.

Even assuming that we ultimately lose China and thus have 21 races once again, is Honda capable of producing a power unit that can complete seven weekends – without sacrificing the performance that allowed Red Bull to compete for poles and wins last year? In terms of mileage that would be a major leap from where it was in 2019.

Or has it already made the tactical decision to use four units, reducing the target per engine to five or six weekends – but ensuring that there are penalties at some point in the last third of the season?

That would be a huge call to make given the title aspirations, but it's one that Red Bull may have had to sign up for. The plus side would be the likely guarantee of an extra upgrade step late in the season, and possibly the freedom to use higher modes for longer within that five-six race per unit schedule.

Within the Red Bull camp there's a positive feeling about Honda's progress.

"They look quite happy," team boss Christian Horner said last week. "The engine made constant progress throughout last year. This latest engine is the next step in that evolution.

"They've done plenty of mileage on their dynos. We've obviously been working very closely with them and the integration of the engine into the chassis.

"They're very, very focused on making that next step. The turnaround that they've achieved has been phenomenal, when you consider where they were five years ago to where they are now. That's hugely impressive."

Now it's a question how the RA620H package performs in Barcelona testing, and what Honda learns over those six crucial days. Can it tick the required performance and mileage boxes? It's going to be fascinating to find out.