• ANALYSIS: Story of the Year - Valtteri Bottas

Joining a Championship-winning team just a few months before the start of the season is a tough task, but Valtteri Bottas did a brilliant job.

Nico Rosberg's decision to retire from Formula One, just a few days after securing his first World Championship, came as quite the surprise and left a seat vacant at the Silver Arrows. After mulling over their options, the team opted for Finnish ace Valtteri Bottas.

It wasn't an easy position to be in. Valtteri had been at Williams for four seasons and looked set to continue with them, until his Silver Arrows announcement mid-way through January. He was left with a lot to do and not much time to do it in - with lots of fresh faces to meet and a whole new environment to integrate within.

But, Valtteri soon settled in and took it in his stride. Two productive pre-season tests helped him to quickly settle into the team and the cockpit of the W08. By the time the F1 circus rocked up to Albert Park in Melbourne, Australia, Valtteri was feeling optimistic about the season ahead, opening his first Silver Arrows season with third place.

He completed a double-podium for Mercedes, backing that up with third place on the grid in China and missed out on the front row by just one thousandth of a second, equivalent to 5.91cm! Unfortunately, a spin on cold tyres behind the Safety Car dropped Valtteri down the field and he lost more time with a slow pit stop, but battled to make up ground after the earlier mistake and crossed the line sixth.

Valtteri needed to bounce back and he did so in Qualifying for the Bahrain Grand Prix, storming to the first pole position of his F1 career. One milestone ticked off the list and he was focused on securing another on Sunday, but it didn't work out that way and he could only manage third, after struggling with tyre pressures and oversteer.

Thankfully, Valtteri didn't have long to wait for that elusive first F1 victory - it arrived two weeks later in Russia. The Finn qualified third, behind the Ferrari duo, but a brilliant launch from the starting grid catapulted him into the lead and he stayed there right to the very end, holding off Sebastian Vettel to claim his maiden F1 win.

What a way to do it, too! "It's going to take a while to sink in," he said, after the race. "Normally I'm not that emotional but hearing the Finnish national anthem was very special for me. It's all a bit surreal, the first win and hopefully the first of many. It was definitely one of my best races ever. I'm sure this victory will give me lots of confidence going forward."

Spain was the next race on the F1 schedule and despite showing encouraging pace; Valtteri was forced to retire with a mechanical problem - the Silver Arrows' only DNF of the entire year! He was off the podium in Monaco too, after losing time in traffic, but made a noble return in Canada, finishing runner-up to team-mate Lewis Hamilton.

Azerbaijan followed and proved to be one of the most exciting races of the season. It was action-packed for Valtteri, too, and he put in one of his most impressive performances of the year. After clashing with Kimi Räikkönen on the opening lap, Valtteri dropped to last place. But, he was on an absolute charge and stormed up the order, eventually taking P2 from Lance Stroll in a photo finish.

"Today was a crazy race, especially for me," he said at the time. "My main goal today was to fight for the win but that went out of the window after the first lap. I was actually last at one point, but I got my head down, gave it absolutely everything and tried to get the absolute maximum out of every single corner. We didn't quite manage to win but P2 from where we were is a great feeling."

However, he did manage to win in Austria, after taking his second pole position and getting a brilliant start. He had Vettel for company in the closing stages, once again, but he fended off the Prancing Horse's challenge to claim his second win in F1 - and he followed that up with second in Silverstone and third in Hungary - his fifth consecutive race on the podium.

It was a nice way to enter the summer break, but on F1's return, Valtteri suffered a difficult spell of races. He was fifth in Belgium, before finishing runner-up to Lewis in a Silver Arrows 1-2 at Monza and benefitted from the first lap drama to finish third in Singapore; despite feeling he was chasing the car set-up all weekend.

After finishing fifth in Malaysia, he said: "Being honest it may be the most difficult time of my career so far, in terms of how I feel every time I get in the car. I just want to perform, to be on a good level, but I haven't been doing this for some time for various reasons. I was lacking pace and I was sliding around."

But Valtteri found that he learned and took the most out of the tough races, ending 2017 as a better and more complete driver as a result. That showed in the final few rounds, when he found his form and was battling right at the front once again.

He narrowly missed out on a podium in Japan but scored the fastest lap, and was fifth in the USA - battling hard early on, before losing ground towards the end after failing to make a one-stop strategy work.

Rounding out the season with second in Mexico, second in Brazil (which he was slightly disappointed with, after starting on pole position) and a masterful victory in Abu Dhabi was a special way to end a breakthrough year for Valtteri.

"It is crazy to think that last year I was still with Williams, knowing as a fact that I was going to be driving 2017 with them, and now I'm here, winning a race with Mercedes," he said after the finale in Abu Dhabi.

"It's a bit crazy, but life is. It's been an incredible season for me in terms of how much I have learned with this team, with Lewis. I think every single race I've always been able to find something, especially from the tricky ones. I just need to go race-by-race next year but it gives me a lot of confidence."

He was thrown in at the deep end, chucked into a new team with little time to adapt and settle in. But, he did just that. Right on the pace and snapping at Lewis' heels, it was a rollercoaster first season at the Silver Arrows for Valtteri.

But, it also proved to be a landmark year for him too, and he's fully focused on achieving even more exciting milestones in 2018.