Fernando Alonso gave Ferrari fans at Mugello something to cheer about with the fastest time in the opening test session.
Alonso clocked one minute 22.444 seconds, a significantly quicker time than anyone else could produce in conditions that dried out during the session.
The teams were congregating in Italy for the first in-season test to be allowed in four years.
The test is crucial to Ferrari, who have endured a poor start to the season bar Alonso's win in the rain in Malaysia.
His time was more than a second quicker than Mark Webber could manage in the Red Bull with Toro Rosso's Jean-Eric Vergne a distant third.
Jerome d'Ambrosio was fourth fastest as the ex-Virgin driver got his first taste of the Lotus E20 - he hands over to Kimi Raikkonen and Romain Grosjean for the last two days of the test.
Nico Rosberg overcame some early technical trouble to post the fifth fastest time ahead of Kamui Kobayashi and Oliver Turvey, who was driving the only McLaren in action.
