Latvian national team star Sandis Valters erupted for 29 points, including eight in overtime, as ASK Riga edged Maroussi 92-88.
Riga were beaten soundly last time out by Dynamo Moscow Region but the players and their coach, Ramunas Butautas, hit back impressively in this Round II showdown.
Renaldas Seibutis had 26 points and none of his shots were bigger than his three-ball with five seconds remaining in regulation to level the contest at 80-80.
Maroussi's Curtis Millage had a chance to win right before the death but his jump shot was off target.
Valters, who will represent his country at the EuroBasket, took his points tally to 24 when he struck from behind the arc to give Riga an 83-80 lead, only for Konstantinos Charalampidis to pass to Seibutis and the former Olympiacos player to hit another three - his third of the game - with 4:18 to go in the extra period.
But Valters was on fire, and when Millage spotted him open, he nailed another three-ball with 3:11 to go for 86-83 Riga lead.
They stayed in front the remainder of the contest.
Maroussi didn't give up with Markos Kolokas tapping in a missed shot to make it 86-85, and later, with just 16 seconds remaining, Charalampidis drilled a three-pointer to trim the deficit to 89-88.
Charalampidis fouled Valters, though, and he sank both free throws for a three-point lead.
Charalampidis then turned the ball over with 10 seconds to go and ASK Riga added a free throw for the four-point win.
Riga improved to 1-1 in Group J while Maroussi are 0-2.
Butautas, recently appointed as Lithuania national team coach, had a couple of reasons to be happy.
Not only did his side win, but he got a great look at a Seibutis who could help the Lithuanians this summer in Spain at the EuroBasket.