Jesualdo Ferreira's league leaders began strongly and went ahead thanks to an early strike from Portuguese midfielder Zeka which silenced the raucous 33,000-capacity home crowd at the Georgios Karaiskakis Stadium.
But Olympiakos rallied with Rafik Djebbour's strike just after half-time leveling the scores to set up a tense finish with the hosts unable to convert several chances to win the match.
The result means both teams remain unbeaten after eight matches but Panathinaikos lead the standings with 20 points ahead of the Reds who are second on 18.
After a cautious start from both teams Panathinaikos broke the deadlock with their first attack.
Kostas Katsouranis sent Quincy down the right channel with a clever through ball and the Ghana forward skipped past the challenge of Avraam Papadopoulos before crossing for Zeca to tap home from close range after 16 minutes.
Sebastian Leto, who spent the 2009/10 season at Olympiakos, almost made it 2-0 but his long-range strike hit the post before Olympiakos responded strongly to create a series of chances.
Djebbour's shot was brilliantly pushed around the post by 17-year-old Panathnaikos goalkeeper Stefanos Kapino just past the half-hour mark before David Fuster hit the post with a first time effort.
Olympiakos pulled level two minutes into the second half when Kevin Mirallas broke clear down the left and crossed for Djebbour to slot the ball into the net from about five metres to spark frenzied celebrations from the home crowd.
The hosts came closest to grabbing a winner with Mirallas passing up a couple of decent chances and Kapino saving a late Fuster shot from close range.
AEK Athens are fourth on 16 points after a 2-0 home win over Asteras Tripolis with goals by Nikos Liberopoulos and Leonardo while Kerkyra beat visiting Ergotelis 2-1.
