Alex Campbell missed a three-point shot with one second left in the fourth quarter as the Niagara River Lions beat the Rattlers 99-97 in Saskatoon.
Guillaume Payen-Boucard led the way for the Lions with 19 points and six rebounds.
Trae Bell-Haynes added 18 points for Niagara River.
Tavrion Dawson had 29 points and seven rebounds in the loss.
The Lions shot 60 per cent from the floor and the Rattlers 58 per cent.
The first points in the new league were scored by Negus Webster-Chan, who was fouled while making a successful three-point jump shot, and then sank his free throw.
The Rattlers are back in action Saturday when they travel to Ontario to take on the Guelph Nighthawks.