British Superbike championship leader Leon Camier fought his way from 17th to sixth for Airwaves Yamaha, with former British Superbike champion Ryuichi Kiyonari
(Ten Kate Honda) narrowly separating Camier from team-mate James Ellison.
Ruben Xaus claimed a welcome ninth for BMW with wild-card Simon Andrews an excellent tenth - from just 26th on the grid - to finish as the top Kawasaki rider. A bad day for Suzuki saw the top GSX-R1000 of Yuki Kagayama cross the line in 13th position, with new team-mate Blake Young 17th.
Joining Haga and Biaggi in hitting the asphalt was Biaggi's team-mate Shinya Nakano, who highsided spectacularly on the exit of the Old Hairpin while holding an early third, plus Carlos Checa
(Hannspree Ten Kate Honda), Jakub Smrz (Guandalini Ducati) and AMA star Jamie Hacking (PBM Kawasaki).
Hannspree Ten Kate Honda's Jonathan Rea spun out of sixth at the final turn on lap two before finishing 15th.
Stiggy Honda's John Hopkins, an impressive eighth in only his third WSBK race earlier in the day, didn't start race two due to pain from his healing injuries.