Panionios will go into their must-win clash at home to Spirou Charleroi in the EuroCup on the back of a thrilling 96-93 triumph over strugglers AEL Larissa.
Luka Pavicevic's men led by as many as 16 points in the second quarter but were unable to press home their advantage and found themselves knotted at 91-91 inside the final minute after AEL got two free throws from Arthur Lee and a basket from Giorgos Tsiakos.
Kennedy Winston replied for Panionios, only for Nikolaos Papanikolopoulos to level the scores again at 93-93 with 11 seconds remaining.
Winston then left the home fans celebrating, and breathing a sigh of relief as he buried a three-ball one second from the end for the victory.
Andre Hutson had 29 points and Winston 20 for Panionios, who are sixth in the Greek standings.
In the EuroCup, they are 2-3 in Group J.
Unlike Panionios, Maroussi are already out of contention for a place in the quarter-finals of the EuroCup.
With their focus now firmly on trying to reach the play-offs in Greece, they won 86-69 over AEK.
Maroussi are ninth in the top flight with seven victories and 10 defeats.
At the top of the table, Olympiacos won at Panathinaikos.
Andrija Zizic led five players in double figures with 18 points for Pini Gershon's team, who won 89-84.
The result has left Panathinaikos (15-2) one point clear of Olympiacos
(14-3) in the regular season title race.