Hamburg did almost all of the attacking but were denied by visiting goalkeeper Mark Schwarzer who was in inspired form, denying Jonathan Pitroipa, Piotr Trochowski and David Jarolim in quick succession midway through the second half.
Fulham, playing the 17th match of a Europa campaign which began in Lithuania in July, were forced to make the 1,000-km journey by road because of the widespread disruption to flights across Europe.
"It was not such a bad result, if we score once in the return (next Thursday) they must score two and I think they will have to come out and attack more than they did today," said the Croatian who came on as a second-half substitute.
Trochowski went close with a 25-metre effort before Zoltan Gera had Fulham's best effort, a 20-metre shot which took a deflection.
The Australian did well again to get his fingertips to Trochowski's dipping 30-metre drive and stop a Jarolim effort which went through a crowd of players.
Joris Mathijsen then foiled a Fulham counter-attack when he cut out Gera's pass to Clint Dempsey.
Petric added some bite to Hamburg's attack, forcing Schwarzer to make another difficult save before narrowly missing the target with a long-range effort.
