Duop Thomas Reath powered Al Riyadi with a season-high 34 points --spiked by a quartet of 3-pointers-- and 10 rebounds in over 38 minutes of play.
Behnam Yakhchali led Gorgan with 20 points.
Al Riyadi has now taken the 1-0 lead in the best-of-3 affair, and could wrap it up at home on Wednesday at the Nouhad Nawfal Sports Complex in Beirut.