Nottingham Forest climbed up to fourth in the Sky Bet Championship with a thumping 4-0 win over 10-man QPR.
Rangers lost Lee Wallace to a red card early in the second half and are now six matches without a win, their encouraging start to the season having evaporated in recent weeks.
Alarmingly, they have conceded two or more goals in their last 10 matches, equalling a sequence set by the club just once before, in 1951.
They are also still the only team in the entire English Football League not to manage a clean sheet this season, and it was easy to see why.
On the half-hour Rangers failed to clear another corner and were grateful to see Sammy Ameobi's flick land straight in the arms of Lumley.
Rangers manager Mark Warburton was facing the club who sacked him in 2017 for the first time, and his chances of revenge looked even bleaker after last-man Wallace was dismissed for tugging Lolley to the ground.
Yet Rangers should have been level on the hour after Josh Scowen met Kane's cross eight yards out in front of goal, only to plant his header wide.
Figueiredo almost helped himself to a second only to see his header cleared off the line by Scowen, but in the 81st minute Grabban doubled the lead, arriving at the far post to finish Ameobi's cross.
Rangers promptly collapsed and Carvalho skipped around a couple of non-existent challenges for the third before fellow substitute Semedo tapped in a stoppage-time fourth.