The Third Division side booked their place in the last eight of the Scottish League Cup, steamrollering their recent peers in a confident home performance at Ibrox
Ally McCoist was missing midfielder Ian Black, who pulled out with an injury, but handed a start to Spanish striker Francisco Sandaza, despite the former St Johnstone man having an inconsistent start to his first season at Ibrox.
His opposite number and former Ibrox team-mate, Stuart McCall, was able to name the exact same line-up that started against Aberdeen on Sunday, where the Fir Park outfit regained top spot in the SPL, though they were unable to prevent the loss of their unbeaten domestic record at Ibrox.
Both defences looked shaky early on as Fraser Aird for Rangers and Chris Humphrey for Motherwell both looked lively as they took on their opposition full-backs and played balls into the box but neither could get the final ball in.
McCoist was handed a blow with halfway through the first half as Sandaza was involved in a nasty clash of heads with Motherwell defender Shaun Hutchinson, which saw the Rangers striker stretchered off, while Hutchinson was forced to get stitches.
The best chance of the first half came as Nicky Law broke the Rangers offside trap after a quick free kick from Motherwell and as the English midfielder raced in on goal, Neil Alexander came out of his box, clearing the ball from danger after a poor touch from Law.
After some early pressure at the start of the second half from Motherwell, it was the home side who took the lead as a short corner taken by Fraser Aird reached Shiels, who crossed the ball onto the head of McCulloch, the forward bulleting the ball home.
The home side doubled their lead shortly afterward as a cross from the left by Lee Wallace was missed by the Motherwell defence, allowing Anestis Argyriou to get the ball on the right and, with the visiting defence sleeping at the back he found Shiels all alone, the Northern Ireland international making no mistake from close range.
Motherwell could have got back into the game on the hour mark as Tom Hateley curled a free kick from the edge of the area, which Alexander had to get down well to in order to divert away from the Rangers net.
The visitors made a couple of changes, with both Omar Daley and Jamie Murphy coming on as they looked to kick-start a fightback in the game, but they could find no way past Alexander and the Ibrox side took their place in the quarter-finals.