Behind Fabrizio, hotly tipped rookie Ben Spies was an impressive second best on the Yamaha, the American edging out Max Neukirchner on the Suzuki, even if he was some three tenths down on Fabrizio's best.
Neukirchner's team-mate Yukio Kagayama led the way early on, but while he eventually slipped to fifth, Suzuki will be encouraged with the strong early pace of their K9 GSX-R1000.
Aprilia's Shinya Nakano was also one of the day's stars as he belied his lack of Superbike knowledge in an excellent sixth place. Given how new the RSV-4 still is, the team will be pleased to see Nakano getting to within half a second of Fabrizio's leading pace.
Team-mate Max Biaggi, who missed much of the day after a series of problems with his flight, was just behind in seventh, albeit six tenths off Nakano, but ahead of Ryuichi Kiyonari, who led Ten Kate Honda's fairly quiet challenge. Team-mates Carlos Checa and Jonathan Rea, who collided with Haga early on, were 11th and 12th respectively, but completed just 26 laps between them.
WSBK - Kyalami - First day Pirelli test
01 Fabrizio (Ita-Ducati) 1′41″204 (66 giri)
02 Spies (Usa-Yamaha) 1′41″599 (46)
03 Neukirchner (Ger-Suzuki) 1′41″713 (69)
04 Haga (Jap-Ducati) 1′41″730 (31)
05 Kagayama (Jap-Suzuki) 1′41″755 (39)
06 Nakano (Jap-Aprilia) 1′41″846 (51)
07 Biaggi (Ita-Aprilia) 1′42″446 (29)
08 Kiyonari (Jap-Honda) 1′42″744 (62)
09 Corser (Aus-Bmw) 1′42″975 (33)
10 Xaus (Spa-Bmw) 1′43″274 (41)
11 Checa (Spa-Honda) 1′43″418 (10)
12 Rea (GB-Honda) 1′44″496 (16)
13 Sykes (GB-Yamaha) 1′46″780 (16).