Guildford brushed off Saturday's agonising overtime defeat at Newcastle to beat the Leicester Riders 69-65 and make the BBL Cup quarter-finals. England international Michael Martin scored 17 points to lead the Heat, who only joined the league this year.
Elsewhere, the Scottish Rocks' Frank Bennett netted 25 points against his former club Newcastle in a 72-71 win.
Brighton beat London Towers 88-81 and Milton Keynes remain unbeaten after an 88-81 win at Sheffield.