The British No 1 and world No 10 had to work hard for his win against the German who had lost his last 11 matches.
Rusedski, playing his first tournament since splitting with his coach, Brian Teacher, could not be faulted for positive play in the first set. But, in rushing to the net on every point, Rusedski paid the price against the accurate groundstrokes of the Czech-born German.
Rusedski dropped his opening service game, but he quickly levelled at 2-2 only to be unable to convert a break point for a 4-2 lead.
That proved expensive as some searing returns from Prinosil brought him a second break in the ninth game and with it the set.
At that stage Rusedski's first serve, normally the foundation of his game, was regularly misfiring and when he lost his composure after being foot-faulted and squandered a 4-2 second set lead, he looked in real trouble.
Suddenly the fourth seed turned anger into aggression, claimed eight successive points and was level at one set all. The decider went with serve, with Rusedski crucially saving a break point at 4-4 with a good serve and volley.
Three games later he produced some sparkling groundstrokes to break the Prinosil serve for the fourth and final time.
Afterwards Rusedski denied feeling any pressure at now being ranked in the world's top 10. "It just makes me look forward to competing and doing my best" he said. "It's good fun and you get even more excited to play."Reuse content