Lewis Hamilton: It's been good to have a break after Russia. Over time you reflect on each race weekend and what you might have done differently, so you can learn from each experience and move on. I'm really proud of the guys in the garage: we've had a hard time but they're doing a fantastic job and I'm really happy with how we've been working together. Every weekend, we've got the car into a great place setup-wise - I just haven't been fully able to exploit it. So the glass is half full for me. It will be a big challenge but there's a long way to go with 17 races left and, if the last four are anything to go by, there's a lot more still to come from us. The team has been on it 24/7 since returning from Russia so I'm confident they'll get to the bottom of the problems we've been having. I know I'm still quick. I've known that since day one in testing and, when I've had clean air and a damage-free car this season, I've shown it on track. I head to Spain confident of a good weekend.

Nico Rosberg: It's not something I could have expected - winning the first four races of the year. It's been a great start but I'm just enjoying the moment and the form I'm in, doing my best to keep it going and hoping I can carry it through to the end of the season. Sport is all about ups and downs and being mentally prepared to bounce back stronger when they come. With a season this long you have to just take things race by race. There are 425 points still up for grabs - and anything can happen yet. Next up, it's Barcelona. I got my first pole and win at this circuit last year and I'm connecting really well with the car at the moment, which is great as it gives you this awesome confidence to push the limits. So, I'm excited for the weekend and no doubt a big battle ahead.

Toto Wolff, Head of Mercedes-Benz Motorsport: Assessing our season so far is an interesting task. On the one side, we are leading the Constructors' Championships by a good margin and our drivers hold the top two positions in the Drivers' standings. So, realistically speaking, it's tough to ask for more. However, it has not been plain sailing and we have had problems that we are working hard to solve. We have rivals breathing down our necks who are relentless in their chase. The longer regulations remain stable, the harder it is to find extra performance. We are pushing the limits to ensure we remain competitive - but if you push the limits then at a certain stage you risk stepping over them. The whole team, on both the chassis and Power Unit side, is working flat out to extract every millisecond from our package without compromising reliability. This is a group of great engineers and I have no doubt that they are going to achieve that. We are always learning as a team. In Hungary and Singapore last year, we took a couple of big hits. But we came out of those races stronger and we continue to learn from our struggles. We're going to see some big upgrades from the different teams and Power Unit suppliers over the next few races, so now is the time we can truly assess the pecking order. Barcelona will be an interesting weekend from that perspective, so we must be prepared.

Paddy Lowe, Executive Director (Technical): The first European race on the calendar traditionally marks the beginning of a new phase of the season. Most of our race freight has been away since early March, so it gives us a chance to refresh the parts and equipment as we transfer everything out of the air freight and over to the race trucks - a busy time for the race team! Barcelona itself is a circuit which is very demanding of all aspects of car performance. There's a common saying in Formula One that if you're quick around Barcelona, you'll be quick everywhere. This makes it an important landmark in the season to see where you stand in performance terms, as most teams will be bringing a range of upgrades. Of course, we've all been to this circuit already in 2016 during winter testing - but it's a very different track in May compared to how it was back in March. It will be much warmer and the tyres will behave differently. We have the Hard, Medium and Soft compounds to choose from, which presents some challenges. The Soft will be essential for qualifying but not be a great race tyre, so determining the optimum strategy will be a focal point. Qualifying and race starts will also be important, as it is notoriously difficult to overtake at this circuit. But the highest priority is to come back with our MGU-H problem solved, having had a repeat fault over the past two race weekends. The team has been working day and night to understand it and we're targeting a clean weekend all round.