Rangers 3-0 Kilmarnock

• Rangers reach Scottish Cup fifth round

• Nicky Law scores Ibrox double

• Kris Boyd scores 15th goal against former club

Rangers moved into the Scottish Cup fifth round at the expense of Kilmarnock, whose challenge faded.

The Ayrshiremen rarely threatened Rangers goalkeeper Steve Simonsen at Ibrox and struggled to recover from Nicky Law's first-half strike.

Played before a crowd of only 14,412, Kris Boyd drove home his 15th goal in 16 matches against his former club a few minutes after coming on as a sub.

And Law rounded things off with a superb long-range curler in 84 minutes.

This was two teams seeking to redeem themselves. Rangers were still smarting from their league defeat to Hearts the previous weekend, while Kilmarnock came into this cup tie on a run of four straight defeats.

The expectation was, still, of opponents whose confidence was bruised and fragile. Command would be a precious commodity, and neither side was able to show it for most of the game, but that kept it finely balanced while the scoreline was still only 1-0 to Rangers.

A crowd of 14,412 watched Rangers knock Killie out of the Scottish Cup

The home side were immediately sprightly, and Lewis Macleod signalled his intent to be a key influence with an early burst into the Kilmarnock penalty area but he pulled the ball across the face of goal and wide.

The threat could be carried to Kilmarnock by turning the defenders and getting the ball in behind the back line. Fraser Aird made plenty of forays to the bye-line without producing a telling cross.

Yet Rory McKenzie did the same for the visitors, at least early on, and when the Kilmarnock winger evaded a rash diving challenge by Bilel Mohsni, he pulled the ball back for Alexei Eremenko but his shot was deflected wide by Lee McCulloch.

With the contest finely poised, good fortune intervened for Rangers. When the ball broke at the edge of the box from a corner kick, Aird wanted to surge into the penalty area, but was impeded by the referee Brian Colvin, so instead he slid the ball to Law.

The midfielder swept a shot towards goal that toll a deflection on its way past Craig Samson, the Kilmarnock goalkeeper.

Rangers also thought they should have won a penalty when Kenny Miller was tackled by Ross Barbour. The Kilmarnock full-back appeared to make contact with the ball, but may also have done so by fouling Miller. Even so, the frustration did not linger.

The goal provided a surge of confidence and momentum for Rangers and Macleod finished a neat piece of skill with a left-foot volley that Samson plucked out of the air.

Ian Black also shot wide from 20 yards out, and there was some comfort to the home side's play while Eremenko, McKenzie and Tope Obadeyi on the left flank were all starved of the ball.

Kilmarnock will have felt that there was still an opportunity to trouble Rangers' state of mind while the lead was so slender, but the home side's defence was generally sound. Kilmarnock's double substitution - bringing on Jamie Hamill and Robbie Muirhead - had little effect but when Rangers brought in Boyd and Nicky Clark there was an immediate impact.

The pair combined for an early chance that was cleared, then when the ball broke to Boyd from a corner, his second touch brought some space inside the area and his third drilled the ball into the net.

Rangers' second goal was enough to suppress any hope that Kilmarnock had left. There was still room for a flourish, though, and a quick, purposeful counter-attack involving Macleod and Richard Foster ended with Law curling a shot beyond Samson's reach and into the far corner of the net.

Kris Boyd scored within two minutes of coming on as a sub to replace Jon Daly

Rangers sub Nicky Clark is outnumbered as Kilmarnock goalie Craig Samson punches the ball clear

Rangers striker Jon Daly attempts some acrobatics in the Kilmarnock box