Leicester fought off a rousing finish from Gloucester to win a thrilling match 17-12 at Welford Road and jump two places to second in the Aviva Premiership.
Trailing by five points, Gloucester threw everything at Leicester in the final few minutes and were twice thwarted by the Tigers' last-ditch defence on the line.
Anthony Allen scored the only try of the match against his former club seven minutes after half-time following intense pressure from a Leicester pack that dominated a match in which four players were yellow-carded.
Leicester's other points came from fly-half George Ford, who kicked three penalties, and Geordan Murphy who added another. Fly-half Freddie Burns slotted four for Gloucester.