The defeat was Jay Marriott side’s eighth in a row in all competitions and they remain 10 points off a play-off spot with just nine matches to go.
Sunday’s match was quite even until half-time, with Lions just edging it 46-43.
But in the third quarter the visitors, inspired by Makal Stibbins, pulled away and finished the period 71-64 up.
Raiders, who had endured an over-time defeat at Sheffield on Friday night, could not pull the game back in the final 10 minutes.
Stibbins was the star of the show, scoring a game-high 32 points.
Jordan Clarke was Raiders’ top scorer with 21.
Raiders, who are 11th in the 13-team BBL Championship, are not back in action until March 26 when they entertain Durham Wildcats.