Rafik Djebbour scored twice as Olympiakos came from a goal behind to take control against the run of play at the Olympic Stadium, but Spanish striker Toche grabbed a 66th minute equaliser to rescue pride and a point for the Greens.
The result left unbeaten Olympiakos on 36 points, with PAOK Salonika second with 28 after their 1-0 home win against Levadiakos on Saturday.
Panathinaikos are seventh, 16 points off the lead, after the 148th match between the arch-rivals.
Coached by Argentine Juan Ramon Rocha, Panathinaikos deservedly went ahead after 17 minutes with a flowing move that Charis Mavrias finished with style off a Nikos Spyropoulos' cross.
The lead lasted just five minutes as Djamel Abdoun broke down the left channel and crossed low for Djebbour to smash the ball home from close range for the equaliser.
The hosts continued to push forward but went 2-1 down four minutes after the half-hour mark when Djebbour was left unmarked to nod home David Fuster's corner for his 11th goal of the season.
Panathinaikos pushed hard for an equaliser with Lazaros Christodoulopoulos going close from long range before the breakthrough came in the 66th minute with Toche bundling home from Mavrias' cross.
PAOK Salonika kept up the pressure on the league leaders with Lino's solitary second-half strike.
Last placed AEK Athens will look to continue their recent improved form and move away from the relegation zone when they visit Panthrakikos on Monday.