Grosjean beats Button's time in Barcelona
Romain Grosjean made sure Lotus' return to testing was a positive one by going fastest on day one of the final pre-season Formula 1 test in Barcelona.
The Frenchman waited until there was less than 30 minutes remaining for the day before he set the benchmark time of 1m23.252s, using a set of Pirelli's soft tyres to eclipse Jenson Button's fastest time from the morning's session.
Faster times were a rarity in the afternoon sessions, with teams opting to use the stable track conditions to go for longer runs. Grosjean was one of only two drivers to improve after lunch, the other being Red Bull Racing's Mark Webber.
However, Webber was only able to shave a tenth off his best morning time, leaving him behind Button and Perez - both with morning times in fourth for the day.
Behind Webber it was Nico Rosberg, the Mercedes driver the busiest of the day with 128 laps for the day, mostly completed over long stints. Jean-Eric Vergne was sixth fastest, with Toro Rosso dedicating much of the last hour to pitstop practice.
Felipe Massa had a busy afternoon, eventually completing 105 laps for the day, despite a lengthy stay in the pits after lunch. However, his best time was only good enough for eighth.
His reward was avoiding the bottom of the time sheets, with Petrov ending the day 0.711s clear of Pastor Maldonado, the Williams driver completing the least number of laps for the day with just 58.
Testing resumes tomorrow at Barcelona.
Pos Driver Team Time Laps
1. Grosjean Lotus 1m23.252s 73
2. Button McLaren 1m23.510s +0.258 64
3. Perez Sauber 1m23.820s +0.568 118
4. Webber Red Bull 1m23.830s +0.578 102
5. Rosberg Mercedes 1m23.992s +0.740 128
6. Vergne Toro Rosso 1m24.216s +0.964 113
7. Di Resta Force India 1m24.305s +1.053 98
8. Massa Ferrari 1m24.318s +1.066 105
9. Petrov Caterham 1m24.876s +1.624 123
10. Maldonado Williams 1m25.587s +2.335 58