BARCELONA, Spain - Ex-McLaren driver Lewis Hamilton wrapped up his pre-season testing with Mercedes in eye-catching style on Saturday with a lap easily the fastest so far here.The 2008 Formula 1 World champion will make his Mercedes race debut in Melbourne on March 17 with the Circuit de Catalunya time sheets showing 1min20.558 from the penultimate day.Germany's Nico Rosberg will complete testing for the team on Sunday.2485km IN NEW CARWhile not too much should not be read into test-lap times, his lap was a second quicker than his fastest time in qualifying for the 2012 race there (1min21.707) and well inside Kimi Raikkonen's 2008 race lap record of 1min21.670.Hamilton put in 117 laps on Saturday (545km) to take his pre-season distance covered in the new F1 W04 car to 2585km and he's set the fastest time on two of the 13 days so far."We were able to get through all the test items that we wanted to achieve by the end of my programme," he said. "There's still a lot of work to get to where we want to be but the team is doing a great job."The reliability, the mileage and the step-by-step improvements we have achieved during the three tests are all very encouraging but we haven't seen the full potential of our competitors yet so it's difficult to predict where we might be."His former McLaren team mate Jenson Button took notice on Friday when he said: "The one team that has been consistently quick has been Mercedes."Ferrari's Felipe Massa was second on the time sheets, also wrapping up his pre-season testing, with 1min21.266. Adrian Sutil was third for Force India after an impressive 109 laps by the back-in-F1 German.Massa had to stop on track with less than half an hour remaining when his car's left front wheel came off.The team, whose F138 car has also looked a lot more competitive than the old F2012 this time in 2012 with Fernando Alonso saying it was "200 times better", blamed a suspension problem.'PRETTY GOOD ONE'Frenchman Romain Grosjean made an unexpected return to the Lotus pit after flying home to Paris on Friday night thinking his testing work was over, only to be summoned back to Spain when team mate Raikkonen reported sick.Italian reserve Davide Valsecchi filled in for Raikkonen."I certainly didn't expect to be in the E21 again today so it was an interruption to a day off, but as interruptions go it was a pretty good one," Grosjean said. "I was able to assess the new wings, which feel better than the first versions. We ran with high fuel so it wasn't about lap times in the afternoon, rather about valuable data we're getting for the car."Australian Mark Webber wrapped up his testing for 2012 champion team Red Bull with the seventh-fastest time."We had a few small issues with the car which delayed us a couple of times. While it wasn't ideal I think we still learned plenty." Stay with Wheels24 for the 2013 Formula 1 season – fresh reports every day.