The Australian Ducati rider retired from the first 25-lap leg with a seized engine but came back to dominate the second leg.
Britain's Carl Fogarty, the defending champion, had an encouraging first outing that earned him fifth place. But he disappointed the crowd of 57,000 by crashing out in the second leg.
Fogarty has struggled since switching from Ducati to Honda after his 1994 and 1995 title wins. He has scored only two victories so far over the quicker Italian machines. "That was the best I could do," he said after the first race. "I was hanging on in there for everything I could get.
"I'd like to get a better result for the crowd at least. They were going wild every lap and I was only in fourth or fifth place."
Pier Francesco Chili won a thrilling opening race on his Ducati after a wheel-to-wheel battle with Anthony Gobert's Kawasaki. The lead changed repeatedly, but the Australian Gobert's gamble on an untried rear tyre robbed him of the speed to stay ahead of the Italian.
American John Kocinski set a new super bike lap record on his Ducati while chasing the leading pair to the chequered flag, but he crashed out of race two.
Corser set an early pace in the second leg. "I got carried away with enthusiasm and almost went over the handlebars on the last lap," he said. "But I made a good start and built up a lead so that when the tyres started to go off I had enough in hand."
Corser's first-race failure handed a temporary world championship lead to Aaron Slight, Fogarty's New Zealand team-mate, who finished sixth.
The second-race success restored Corser to the top of the table by eight points from Slight, with Fogarty third.
Alex Criville of Spain created an upset in the Austrian Grand Prix yesterday when he snatched a last-lap victory from the 500cc world championship leader, Michael Doohan, of Australia. Criville, riding a Honda, forged ahead on the penultimate curve of the 28-lap course.Reuse content