What to Watch for - Spain

From the critical nature of the start to Rosberg to Renault's encouraging prospects, and from Sainz carrying the home fans' hopes to a possible surprise showing from Force India, we break down the key story lines to watch out for in Sunday's Formula 1 Gran Premio de Espana Pirelli 2015 at Barcelona...

Start more crucial than ever for Rosberg

At 730 metres, the run from the start line to the first corner at Barcelona is one of the longest in Formula One racing. And on Sunday, those first 730m will shape the tone of the entire race. For Rosberg, it’s a must-not-lose situation.

Few other circuits are as notoriously difficult to overtake on. It’s why eight of the last 10 polesitters have triumphed, and why last year’s race here featured just four non-DRS assisted overtakes. For Rosberg, and for Hamilton and Vettel behind him, that means winning the run through the first few corners is absolutely vital.

Consider also Rosberg’s record from pole last year. Of the eight times on which he took the first spot but had Hamilton directly behind, he managed to keep the Briton tucked up for the entire race on just two occasions - Monaco and Brazil. As is the case this weekend, overtaking opportunities are limited at both venues. And as is also the case, Rosberg simply must take advantage of that in order to disrupt Hamilton’s momentum and reignite his own title charge. As he said on Saturday, securing pole is just a step in the right direction to victory. Keeping the advantage from the start will be a major stride...

Sainz aiming to give home fans something to shout about

Fernando Alonso has given the fans in Barcelona plenty to cheer about over the years, including victories in 2006 and 2013. But with the double world champion currently hamstrung by McLaren’s lack of performance, the home fans needed a new hero to challenge towards the front of the field, and in Carlos Sainz they have got just that.

To the surprise of many, the Toro Rosso rookie steered his STR10 to a superb fifth place on the grid - his best qualifying performance to date - and has now given himself every chance of improving on his current best finish of eighth (achieved in Malaysia).

However, after extracting every drop of performance from his car possible on Saturday, the 20-year-old is under no illusions as to how hard it will be to retain such a lofty position in the race, not least because Toro Rosso’s long-run pace on Friday was not as strong as that of many of the cars starting behind him.

“It won’t be easy to finish the race in the top five, but it’s free to dream and we will try our best to end the race in the highest position possible,” he said. “[In qualifying] I could see all the fans cheering, it was a great feeling and I’d like to thank them all for their support. Let’s push for a good result in the race tomorrow!”

Renault poised for most competitive showing of the season

After a torrid start to the season, Renault arrived in Spain in desperate need of some good news - and on Saturday the French manufacturer got just that. Using a modified specification engine all four Renault-powered cars made it into Q3, with Carlos Sainz and Max Verstappen brilliantly leading the way with fifth and sixth for Toro Rosso, and Daniil Kvyat and Daniel Ricciardo following up with eighth and tenth for Red Bull.

Regardless of Red Bull's slight disappointment, the results from qualifying mean Renault now stand on the brink of their biggest points haul of the season (currently the 13 points they scored in Malaysia), though the spectre of unreliability still hangs over them. Having both taken on a fourth engine this weekend, Kvyat and Ricciardo are now just one failure away from a grid penalty - and that’s the last thing either will want heading to Monaco…

An interesting point to consider is that only once in this season's four races to date have all four Renault cars finished, and on that occasion - in Malaysia - all four scored points.

Pirelli’s medium compound is the race tyre of choice

Given the difference in performance between Pirelli’s two tyre compounds all weekend - which has been anywhere between 1-1.7s, depending on the driver - there’s absolutely no doubt that the teams will all want to do as much running as possible on the medium rubber and as little as possible on the hards.

Knowing this, many of the front-running drivers tried to get through Q1 using only the hard tyre, thereby saving a set of fresh mediums for the race. In the end, only Nico Rosberg, Lewis Hamilton and Sebastian Vettel - the three fastest in Q3 - were able to do so, meaning they enter the Grand Prix with a small advantage over those behind them. Hamilton, incidentally, was the fastest of the three on the hard tyres - something to bear in mind for the latter stages of tomorrow’s race when the drivers should all be running the harder rubber.

Speaking of strategy, a three-stopper is theoretically the quickest option for the 66-lap race, but as is often the case the risk of hitting traffic will more than likely discourage teams from attempting it. Consequently, a two-stop strategy is likely to be the popular choice, starting on the mediums, taking on more mediums on or around lap 23, and then making a final stop for hards at around the 50 lap mark.

Force India should be more competitive than their qualifying positions suggest

The qualifying timesheet made for depressing reading for Force India and their fans, with Nico Hulkenberg and Sergio Perez consigned to the ninth row of the grid. There is, however, a slight silver lining...

During Friday’s long-run simulations in FP2, Mercedes led the way from Ferrari and Williams. But behind them, perhaps surprisingly, were Force India. Despite Hulkenberg’s obvious and repeated frustrations, the team were extremely competitive over representative race simulations, enjoying an edge over McLaren, Lotus and even Red Bull and Toro Rosso.

The bad news, of course, is that they might struggle to unlock that pace given their lowly start. Conditions too might mean their competitiveness falls away. But should Hulkenberg or Perez find themselves with free air, they might just have an outside chance of rescuing something from an otherwise poor weekend for the team.