European champion Panathinaikos forced Olympiakos?s first domestic defeat this season with a 75-70 score on May 26, taking the lead after the first game of the best-of-five finals despite playing in Piraeus.
The Greens have now taken the home advantage in the finals and can stretch their lead to 2-0 with a victory at home in Game 2 on May 29.
The key to Panathinaikos?s triumph was the zone defense that coach Zeljko Obradovic applied from the second period onwards, strangling the Olympiakos attack that had enjoyed a particularly good start to the game.
Olympiakos had the upper hand in the first period, with its lead stretching as far as nine points (21-12) while Panathinaikos was unable to get any points for long spells from its players apart from captain Dimitris Diamantidis.
Yet in the second period Panathinaikos began its comeback to turn a 29-23 deficit into a 32-30 lead through an impressive Aleks Maric. Olympiakos ended the first half with a minimum lead (35-34), but that was about the end of its domination in the game.
Panathinaikos as usual produced a strong third period that saw it turn things around completely and form the game as it suited it.
With one or two tough referee calls going their way, the Greens opened the gap up to eight points (57-49) making the most of their superiority under the basket: They ended the game with 37 rebounds against 32 for Olympiakos.
The Reds had to chase the game and felt the pressure building up, going into the fourth period with a 56-51 deficit.
A good spell saw the host reduce the arrears to one point (58-57) but a persistent Diamantidis and a reliable Mike Batiste kept Panathinaikos ahead despite the absence of in-form small-forward Stratos Perperoglou who was injured.
Olympiakos's last-ditch effort saw it equalize at 68-68, but two key moments that followed sealed the game in Panathinaikos?s favor.
First it was a three-pointer by Antonis Fotsis that made it 71-68 and then an offensive rebound by Batiste that allowed Panathinaikos to hold on to the ball and maintain its lead (73-70) from the line.
The final 75-70 score was the first win for Panathinaikos over the Reds this season after three wins for Olympiakos in the league and the cup.
Olympiakos coach Dusan Ivkovic would have expected more from players such as Thodoris Papaloukas (particularly in the first half) and Milos Teodosic, while Loukas Mavrokefalidis?s inability to match Batiste showed the significance of the absence of injured Rasho Nesterovic.
Diamantidis was no doubt the man of the match with 21 points, nine assists and five rebounds. Maric scored 14 and Batiste 13 for Panathinaikos.
Teodosic and Yiannis Bourousis scored 14 points each for the Reds.