A Kris Boyd goal on the stroke of half time was enough for Rangers to book their place in the fourth round of the Scottish Cup this afternoon.

Ally McCoist's men travelled to Dumbartonshire with goalkeeper Steve Simonsen ruled out, though back-up keeper Lee Robinson was rarely troubled during the first half.

Colin Nish's left-footed shot from outside the box was the closest Dumbarton came to the Gers' goal, while Richard Foster saw a similar effort fizz wide at the other end, letting fly from outside of the box and coming close, but not close enough to trouble Jamie Ewings.

The half looked as though it was going to fizzle out after a stoppage due to a Kenny Miller injury, but on the stroke of half time Kris Boyd broke the deadlock with a right-footed shot from the centre of the box to the bottom right corner, sending the visitors in on a high.

Rangers dominated the second period but, despite a number of efforts on goal, could not find a second goal to wrap the game up.

The closest the hosts came to a goal was an Andrew Graham header, which keeper Lee Robinson got down well to save. His only other serious involvement was a block from a Mitch Megginson shot.

Boyd should have had a second when he found himself in on goal, but Ewings got out quickly to block with his legs. Miller, Lewis Macleod and Ian Black all had decent efforts but were unable to add to the lead.

The draw for the fourth round of the Scottish Cup takes place on Monday.