Fernando Alonso: "It feels great to be back in the car - I enjoyed driving so much today. Maybe I'm not quite 100 per cent fit after two weeks on the sofa and two weeks out of the car, but I'm fit enough to enjoy it out there.

"Today really feels like the second day of testing for me - I had one solid day's running in Barcelona during the winter, when I did 63 laps, and I managed 45 today. Plus, we ran with zero problems - so that's an important step, too.

"We are improving the aero package, gaining a greater understanding of the power unit, and we also have better interaction between everyone working on the car. Every lap is a learning curve for us.

"The car feels consistent and easy to drive, and it's giving me the confidence to push it to the limit. We had some issues with braking consistency today, but we should be able to resolve those overnight. I feel great - I enjoyed today so much."

Jenson Button: "I think everyone found it tricky with today's heat, and it's been tough to find a consistent balance today. A lot of people made mistakes - there's very low grip out there - so the feeling inside the car isn't as good as it was in Melbourne, but our overall pace over a single lap and over a long run is a little closer to the cars ahead of us. That's a step forward.

"We learned a lot today about the engine; we have a bit more power, although we're still learning about driveability in some areas.

"I may have been wrong yesterday when I said that we might not be racing other cars on Sunday: it would be a massive step forward for us if tomorrow we're able to get in among some of the runners currently ahead of us in the pecking order."

Eric Boullier, Racing director, McLaren-Honda: "Today has been a positive day for the whole team. We've worked incredibly hard since Melbourne to improve both the chassis and the power unit, and we definitely saw the results of those efforts during the practice sessions today.

"That's very encouraging, as it shows that we're heading in the right direction with our development programme, but we still have a significant amount of ground to cover before we can regularly fight competitively with the cars around us.

"Still, today has shown a definite step forward in performance - and I hope that we can maintain that momentum for the remainder of a weekend that has already proved more than somewhat arduous for both drivers and machinery."

Yasuhisa Arai, Honda R&D senior managing officer - chief officer of motorsport: "We have been tweaking and developing the power unit for this weekend, and I can confirm that our adjustments have been working positively in both practice sessions.

"However, there is still a big time gap ahead of us, so I'm not satisfied with today's results. Our reliability today has been encouraging, but we still have slight concerns in certain areas because, as ever, the heat is every competitor's biggest challenge around here.

"Tomorrow's practice session will give us a further opportunity to increase our understanding of the data before we head into qualifying."

Check out our Friday gallery, here.