BARCELONA, Spain - Ferrari's Fernando Alonso kept the home fans happy with the fastest time in Formula 1's pre-season testing at Barcelona's Circuit de Catalunya on Thursday February 21, 2013.The Spaniard lapped the circuit with a best time of 1min21.875, the fastest of the week so far, which he set on the soft tyre in the morning before most teams focused on race simulations.MAKING HIS MARKThursday was the double champion's final day in the F138 car this week, after having his first run in it only on Tuesday, with Brazilian Felipe Massa testing on Friday (Feb 22).Lewis Hamilton's fastest time in qualifying at the circuit in last year's Spanish GP Grand Prix was 1min21.707 while Alonso, who ended the season runner-up to Red Bull's Sebastian Vettel, clocked 1min22.302.Alonso said: "We tried various aerodynamic configurations and for the first time, we made some set-up changes to get a good understanding of tyre behaviour and degradation. With every change we made, the car reacted as I expected."Once again this year, the tyres will be one of the crucial aspects to manage: they are softer and quicker, but also less consistent and they degrade rapidly with every lap. We will have a lot of work to do to understand how best to balance the car, but that applies to all the teams."Germany's Nico Hulkenberg was second on the test time sheets for Sauber, 0.285sec slower than Alonso, with Frenchman Romain Grosjean third for Lotus after completing a full race distance on a cloudy afternoon.BUTTON AND PEREZMcLaren's Jenson Button, whose new Mexican team mate Sergio Perez was fastest on Wednesday, ended the penultimate day seventh quickest.Adrian Sutil, returning to the cockpit for the first time in more than a year with the hope of securing the Force India race seat, did 78 laps with the eighth best time and ahead of Australian Mark Webber in Red Bull.Frenchman Jules Bianchi, his rival for the seat, will be testing on Friday when rain is expected.The season will start in Melbourne, Australia, on March 17, 2013.