Rangers boss Walter Smith refused to embroil himself in more refereeing controversy after Kris Boyd was booked for diving during the Co-operative Insurance Cup third round win over Queen of the South at Palmerston.

Smith was sent to the stand during the goalless Clydesdale Bank Premier League draw against Kilmarnock at Rugby Park on Saturday after reacting furiously to Killie players he mistakenly thought were trying to get Pedro Mendes shown his second yellow card and he now faces a four-game ban.

The only real moment of controversy during Wednesday night's win in Dumfries came in the first half, with the visitors leading 1-0 through a Steven Naismith strike, when Boyd went to ground after rounding Doonhamers' keeper Ludovic Roy only to be promptly booked by Willie Collum.

The Ibrox striker was jeered for the rest of the match by the Queen of the South fans but Smith was reluctant to expand upon the issue.

"I don't think he (Boyd) was thinking for a minute that he would get a penalty for it," said Smith.

"But if the referee feels that it is worthy of a caution then so be it - I'm delighted with every referee decision that happens at the moment."

Rangers survived some nervy moments against the Irn-Bru First Division side before a late counter from substitute Nacho Novo eased them into today's fourth-round draw at Hampden although Doonhamers defender Robert Harris did grab a consolation in the dying seconds.

Smith said: "Once Nacho got the second one, I thought that would give us a bit of breathing space but it was breathing space that we needed with them scoring late in the game and they possibly deserved it with the amount of opportunities that they created in the second half.

"But we expected a difficult game and they deserve a lot of credit."

Palmerston boss Gordon Chisholm could find few faults with his side's performance, saying: "I've got nothing but praise for my players and the way they kept going.

"Rangers are an experienced team with a lot of internationals and they got off to a great start.

"It was difficult for us but we just had to try and get a foothold in the game in the first 20 minutes where we were chasing shadows.

"I was disappointed in the two goals in trying to step up and play offside.

"But we kept going and got a late goal but at this level you make mistakes and you are punished."