Playing to an empty arena as punishment for recent fan violence, Maroussi staged a surprise victory over visiting Olympiakos last night to level their best-of-five league semifinal series at 1-1. Maroussi overcame Olympiakos 97-90 in overtime after the rivals ended locked at 81-81 in regular time. The two teams meet again tomorrow at Olympiakos’s Peace and Friendship Stadium for Game 3 in the series. The Athens club reached the semifinals after causing another upset by eliminating Thessaloniki club Aris in the best-of-three quarterfinals, 2-1, following two away victories. Last night, Maroussi rebounded from a poor performance in the series opener to stand firm for most of the game. With the exception of the first 10 minutes of play, Maroussi did what was necessary to achieve victory against the evening’s favorite. Maroussi trailed 16-25 at the end of the first term, led 49-45 at halftime, and sustained its lead for a 66-60 advantage at the end of the third term, before being pegged back for an 81-81 score going into overtime. Later last night, Panionios, trailing 1-0 in its series, hosted defending champion Panathinaikos in the league’s other semifinal.