Serg Ovchinnikov put his team ahead with a 3-pointer with 10 seconds left in the second overtime and the Tigers held on for the non-league victory.
Ovchinnikov had 16 points, six rebounds and four assists for Battle Ground (4-3). Jake Belford had 19 points and 10 rebounds, Jamie Ford scored 14 points and Damien Ford added 12.
Zach Torson scored a game-high 22 points to lead the Thunder (2-2), who got 15 points each from Ryan Johnson and Rico Bolivar, and another 14 from Luke Duchesne.
“It was a great game all the way,” Battle Ground coach Andy Schoonover said. “We got down early and fought back, then they fought back.”