Jorge Lorenzo may have led both Friday practice sessions for his home Spanish MotoGP, but the top five riders were covered by just 0.327s.

Yamaha star Lorenzo thus believes he'll need to find at least another three or four tenths t stay ahead of the pack on Saturday.

Lorenzo lapped under the official Jerez race record in both Friday sessions, including a 1m 39.562s that put him 0.142s clear of countryman Dani Pedrosa (Repsol Honda). Tech 3 Yamaha's Cal Crutchlow was just 0.171s from the top, with Valentino Rossi (Yamaha) and Marc Marquez (Repsol Honda) within 0.327s of Lorenzo.

"At the beginning of second practice I felt better than this morning, but with the warmer temperatures it has been difficult to keep the same pace when the rear tyre wears," explained reigning double world champion Lorenzo, whose best time of the day came on only his fourth lap of the afternoon.

"We will have to work on the settings to keep the same pace for tomorrow. We need to try to improve our pace by three or four tenths, to ride comfortably in the 1m 39s. This will be out goal. To improve by around half a second.

"I'm happy that we are first in today's two sessions, but I want more."

Lorenzo set his fastest lap time on the softer rear tyre and believes the harder option currently offers little advantage, but will try it again on Saturday.

"Some riders assessed the harder rear slick option in FP2 but the consensus is that at this track in the current conditions, the softer rear option is working better," confirmed Bridgestone engineer (and former grand prix winner) Masao Azuma.

Saturday will be Lorenzo's 26th birthday - and see the final corner of the circuit officially renamed in his honour. "This morning when I went through the corner I felt very proud and emotional," Lorenzo admitted.

Lorenzo is currently tied for the 2013 title lead with rookie Marquez, each having won one race so far this year. Pedrosa currently completes an all Spanish top three in the early standings.