The Bears seemed to have ended a run of four successive defeats when Steve Nelson scored a three-pointer two seconds from time to snatch the lead. But Kurt Samuels hoisted a shot from the half-way line as the buzzer sounded to give Derby hope of saving the game.
The table officials and time keeper decided that the England international had released his shot before time ran out, leaving the Bears to slip a further place to seventh in the table behind Derby.
Birmingham Bullets clinched their 12th consecutive league win to move four points clear in third place behind the leaders London Towers and the defending champions Sheffield Sharks.
American Tony Dorsey totalled 60 points in two games as the Bullets silenced 6,000 Manchester Giants fans with a 101-81 win at the Nynex Arena on Friday night, then beat Newcastle Comets 107-77 on Saturday.Reuse content