Citroen's Jose Maria Lopez was fastest on the second day of World Touring Car Championship testing at Vallelunga.
The double champion again split testing duties with team-mate Yvan Muller.
He took part in Thursday afternoon's three 50-minute sessions, but had to wait until the final one for conditions good enough to set a competitive time.
Lopez took full advantage of a drying circuit to post a best time of 1m37.123s - jumping him to the top of the timesheets.
With none of the remainder of the field able to improve their times in the final session, Muller ended the day with the second fastest time.
Muller had set the fastest lap in the first session of the day, lapping the Italian circuit in 1m37.730s in his Citroen C-Elysee.
But by the time he and the remainder of the field had returned to the circuit the weather had set in, with the circuit never returning to fully dry conditions - instead worsening in the afternoon with the arrival of hail.
Polestar's Thed Bjork set the third-fastest time in his Volvo S60, 0.797s slower than Muller, while day one pacesetter Mehdi Bennani was fourth.
Nine drivers set times, with Campos Racing's John Filippi forced to miss the second day of running after a heavy crash in his Chevrolet Cruze on Wednesday.
COMBINED THURSDAY TEST RESULTS:
Pos Driver Team/Car Time 1. Jose Maria Lopez Citroen 1m37.123s 2. Yvan Muller Citroen +0.607s 3. Thed Bjork Volvo +1.404s 4. Mehdi Bennani Loeb Citroen +1.893s 5. Fredrik Ekblom Volvo +2.100s 6. Norbert Michelisz Honda +2.672s 7. Gregoire Demoustier Loeb Citroen +2.921s 8. Tom Chilton Loeb Citroen +3.168s 9. Rene Munnich Munnich Chevrolet +3.248s