Sainz was the right choice for Toro Rosso

Following Carlos Sainz Jr's Formula 1 prospects during 2014 has been a rollercoaster ride, and thankfully it has ended with Red Bull taking the correct decision to place him with Toro Rosso for next year.

The simple fact that he became the first Red Bull-backed driver to win the Formula Renault 3.5 series - which so many of the Austrian firm's young charges have passed through over the years - gave him a very strong case immediately.

In the early part of 2014 it seemed a no-brainer: Sainz was dominating the FR3.5 title fight, winning four of the first seven races.

But his world was turned upside down in August by Red Bull's surprise decision to promote Max Verstappen - a car racing rookie in 2014 - from Formula 3 to F1 for 2015.

Sainz had been made to wait for a verdict from Red Bull on 2015 © XPB

It was a bombshell, and one that hit hardest in Spain. Sainz was doing everything right up to that point, yet suddenly it seemed there was to be no room at the inn.

Discussing the Verstappen news with Sainz towards the end of the summer made for an uncomfortable conversation.

"It was not an easy summer for me," he told me after FR3.5's two-month break. "It's tough to take, and obviously the decision is not to my liking, but I have to be grateful for everything Red Bull has done for me."

Sainz walked the line between expressing some disappointment while still thanking Red Bull. But when asked if he respected the decision, he admitted: "You are putting me in a compromise there!"

Of course he disagreed with the decision. He was adamant he was ready for the step up to F1, and all of the evidence suggested so. After being outshone by Daniil Kvyat when they were team-mates in GP3 in 2013, Sainz returned after the winter having gone from boy to man.

He'd started from scratch with his off-track approach. "I threw away everything except my talent," he says. He was no longer a kid out of the car, and he was delivering in the car.

If he'd thrown his toys out of the pram following the Verstappen announcement, or banged the drum harder about the injustice of seemingly missing out on a promotion to F1, who knows - maybe he would have eliminated himself from contention before a second Toro Rosso seat became available in the wake of Sebastian Vettel's shock switch to Ferrari for 2015, news of which broke at the Japanese GP in October.

But even then - with Sainz recovering from a post-Verstappen-announcement wobble in FR3.5 to continue his march towards the title - it seemed that he was not the automatic choice to slot in alongside the Dutchman.

The mind boggled. It was one thing to overlook him once - maybe Verstappen really is too good a talent for Red Bull to hold back - but to have two Toro Rosso seats up for grabs and for neither to go to Red Bull's first FR3.5 champion seemed like madness.

Performance in 2013 test with Red Bull caught Vettel's attention © LAT

Sainz kept his cool in public. He openly addressed the rumours that Jean-Eric Vergne could be retained to give Verstappen an experienced benchmark, while in the background there was further speculation that FR3.5 runner-up Pierre Gasly had the support of Renault.

The logic behind placing Vergne alongside the inexperienced Verstappen did add up in many ways, but with a credible alternative in the Red Bull junior ranks waiting in the wings, it wouldn't have made sense.

Given that Red Bull had already chosen two other drivers over Vergne to fill vacancies at its world championship-winning team in the past 12 months, how could it possibly condemn Sainz to the scrapheap - without even giving him a shot at racing in F1 - to use one of its Toro Rosso seats as little more than a benchmark?

It didn't sound like the sort of decision you'd associate with the cut-and-thrust Red Bull driver programme, and while many will be sad to see Vergne cast aside, choosing Sainz has to be considered a case of common sense prevailing.

Yes, Red Bull is ruthless with its juniors when they slip just below the required mark while climbing the F1 ladder. Antonio Felix da Costa was the most recent recipient of that treatment, desperately paying the price for losing out to McLaren juniors Kevin Magnussen and Stoffel Vandoorne in FR3.5 in 2013.

But unlike so many Red Bull juniors who could feel hard done by but had ultimately not quite got the job done, Sainz was left hanging despite doing exactly what was asked of him.

Still there was no confirmation of Toro Rosso's second driver, and Sainz's prize for winning the FR3.5 title - a day of post-season F1 testing with none other than Red Bull - was looming.

It was the Spaniard's first proper run in F1 machinery since the summer of 2013, and back then at Silverstone he is understood to have put in an eye-catching performance that even prompted Vettel to offer his seal of approval - once the then-three-time world champion had asked to see Sainz's data and found out how much fuel the youngster had on board.

That performance at Silverstone at least helped Red Bull keep the faith in Sainz, and with the help of the DAMS team that so successfully turned Magnussen into an F1-ready talent in 2013, he repaid that faith this year.

"With Carlos it was not the same as we had with Kevin," says DAMS boss Jean-Paul Driot. "Kevin was over-confident, so I had to bring him down and get him to learn, and to keep him in line for what he wanted to achieve.

"Carlos had to mature a little bit and overcome the fact that the name 'Sainz' is a very big deal in Spain. He needed to not get too excited as soon as there is a little bit of pressure, which can cause mistakes.

Verstappen will join Sainz in an all-rookie line-up for Toro Rosso in 2015 © LAT

"That's what we had to work on with him in order for him to gain confidence and not react with too much passion."

The DAMS approach was successful, but there was more work to be done in the wake of the Verstappen news.

Sainz had an indifferent weekend in Hungary - the first FR3.5 round after the announcement - and Roberto Merhi was chomping away at his points lead. Enter Driot once more...

"I knew that was going to happen," Driot says of the disappointing weekend in Hungary. "Unfortunately I could not be in Budapest.

"We had a very big conversation before [the next round at] Paul Ricard on the Friday night. I took him away from the circuit, away from the team, away from all of the people who are in motor racing.

"It was just me and my wife, and he came and we had a good conversation. Apparently it worked!"

Sainz won both races that weekend, effectively sealing the championship in the process. While Driot had had to get tough with the "over-confident" Magnussen a year earlier, with Sainz it was a case of carefully piecing back together a spirit that had been shattered by his dream seemingly being taken away.

Driver and team dropped the ball at Jerez for the season finale, meaning he was off the pace, but as Sainz declared at the time, the way he sealed the title would be forgotten.

What really mattered was that he had given Red Bull a championship trophy that it had never got its hands on before.

It's likely that in the days and weeks that follow we'll learn just how much of an influence Sainz's performance in Abu Dhabi testing played in the decision to give him the drive.

The fact that he completed 100 laps, including proper development work for the team and some performance running in the afternoon, and it was the following day that Vergne revealed he would not be staying at Toro Rosso for 2015, suggests there might have been a link.

Maybe that day of testing earlier this week was simply the opportunity for Sainz to dot the i's and cross the t's to seal his fate for 2015.