Roenick's tally enabled the Flyers to earn a point after falling behind by two goals midway through the second period.
Philadelphia was held to 10 shots over the first two periods but peppered Evgeni Nabokov with 17 in the third and got the equalizer when Roenick poked in John LeClair's rebound.
Teemu Selanne and Patrick Marleau scored seven minutes apart in the second period, putting the Sharks in front. But a giveaway by Nabokov led to the Flyers' first goal less than two minutes after Marleau extended his goal-scoring streak to six games.
LeClair intercepted Nabokov's clearing attempt and scored on a wraparound with 8:14 left in the second.
Nabokov made 32 saves and came up big during a wild overtime, when the Flyers outshot the Sharks, 7-4.
Robert Esche stopped 27 shots for Philadelphia, which is 5-1-4 at home.
After starting a season-high eight-game road trip with a pair of losses, San Jose is 2
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Arizona Cardinals player formally charged