New McLaren driver Sergio Perez set the fastest lap on the second day of 2013 Formula 1 testing at Barcelona's Circuit de Catalunya on February 20.The Mexican, who moved from Sauber to replace 2008 champion Lewis Hamilton at the team, completed 97 laps - nearly one-and-a-half times the Spanish Grand Prix race distance - with a best time of 1min21.848 on Soft tyres.VETTEL CLOSING GAPPerez did a series of shorter runs in the morning then longer ones in the afternoon focusing on familiarising himself with systems and procedure, including the cockpit switches and radio messaging.Red Bull's triple World champion Sebastian Vettel had been the fastest before lunch, although testing times must be treated with caution since teams are working through different programmes, but was forced to end his session early."We had some issues with reliability today," he said, "and we couldn't do as many laps as we wanted.” The German, who was still second-fastest overall (1min22.197) and did 84 laps. "It was nothing disastrous, just small things that hampered us."The team's race engineering co-ordinator Andy Damerum said the problems would be resolved by the start of Thursday's (Feb 21) session with Mark Webber.Kimi Raikkonen was third on the time sheets for Lotus (1min22.697) although the 2007 champion was sidelined for much of the morning and part of the afternoon by a gearbox problem.'WE HAD A GOOD DAY'Hamilton, now with Mercedes, was fourth fastest in 1min22.726 after completing a whopping 121 laps - the most of any driver - with his best lap set on the Hard tyres in the morning. Hamilton said: "We had a good day and it was nice to get so many laps in. We're making continual steps forward in terms of our understanding of the set-up and the tyres. The guys are working really hard here and at the factory and it's encouraging to see the amount of work that's being put in."We're focusing on our own programme and just getting on with it."Ferrari's Fernando Alonso was fifth fastest.The second session of 2013 pre-season testing will end on Friday (Feb 22). The first race of 2013 will be in Australia on March 17.