Walter Smith's team started well and were two up after only ten minutes through goals by Andrius Velicka and Kris Boyd.
Motherwell reduced the leeway before half-time with a superb goal by John Sutton but Boyd eased any Rangers anxieties with a penalty midway through the second half.
It was another whirlwind start by Rangers with a goal after two minutes. Boyd flicked on a Steven Smith cross which Steven Hammell and Mark Reynolds failed to clear allowing Velicka to force the ball home from close range.
Steven Whittaker made a superb run deep into the Motherwell area but his cut-back fell between Boyd and Velicka.
Rangers went two ahead with a superb shot by Boyd. The striker controlled Whittaker's header before unleashing an unstoppable shot from 30 yards which left Graeme Smith helpless.
Goalkeeper Graeme Smith rescued his side from falling further behind when he raced from his goal to beat Velicka to a superb pass from Pedro Mendes.
Motherwell reduced the deficit with a goal out of nothing. A long clearance reached Sutton who was allowed the time to turn and fire a superb shot into the top corner.
Rangers were clearly rattled and happy to hear the half-time whistle. Graeme Smith saved well from Boyd after the restart before the striker wasted a good chance by pulling his shot wide.
A darting run into the penalty box ended with Brian McLean pulling down Mendes. Graeme Smith was booked for his protests but had no chance when Boyd sent him the wrong way with his spot-kick.
Whittaker nearly added a fourth after another great run into the box but his shot came back off the bar.