Captain Barry Ferguson scored the winner for sluggish Rangers as they closed the gap on league leaders Celtic to four points with two games in hand.
Chances were few and far between in a poor first-half, with Kris Boyd's header against the bar the closest Rangers came to the opener.
Motherwell failed to find a cutting edge and Rangers made them pay.
Steven Davis swung a corner into the box after 74 minutes and Ferguson hooked the ball into the net.
Rangers were looking to close the gap on leaders Celtic, while the visitors aimed to strengthen their grip on third place and a Uefa Cup spot.
Davie Weir hit the bar with a looping header from Davis's corner early on, but after that miss, Motherwell settled into the game.
Ross McCormack spurned Motherwell's best chance of the opening half hour when he sent Stephen Hughes' cross just wide from six yards.
Hughes became more influential before the break and his defence-splitting pass almost sent McCormack through on goal.
Jean-Claude Darcheville, who had failed to make an impact in the game, almost put Rangers in front on the stroke of half-time but his shot flashed just wide.
Within five minutes of the re-start Boyd had sent two headers over the bar with the Motherwell defence all at sea.
Motherwell goalkeeper Graeme Smith scrambled the ball away from the feet of Nacho Novo with 20 minutes remaining as Rangers laid seige to the visitors' goal.
MY SPORT: DEBATE
Ferguson broke the deadlock in the 74th minute when he hooked home from close range after Motherwell failed to clear Davis's corner.
Motherwell never looked like getting an equaliser as the hosts secured their first SPL victory in five matches.
Rangers: Alexander, Broadfoot, Cuellar, Weir, Whittaker, Davis, Ferguson, Thomson, Novo, Boyd (Cousin 86), Darcheville (Adam 76). Subs Not Used: Graeme Smith, Dailly, Lennon, Emslie, McMillan.
Goals: Ferguson 74.
Motherwell: Graeme Smith, Brian McLean, Craigan, Reynolds, Fitzpatrick, Malcolm, Lasley (Darren Smith 75), Lappin, Hughes, McGarry (Clarkson 60), McCormack (Porter 75). Subs Not Used: Daniels, Hammell, Murphy, Meechan.
Booked: Hughes, McCormack, Lappin.
Att: 48,238
Ref: C Richmond
BBC Sport Player Rater man of the match: Rangers' Carlos Cuellar 7.70 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.
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