SHUNSUKE NAKAMURA has been Celtic's set-piece star since his arrival at Parkhead three years ago.

But there is a serious challenger to the title as Barry Robson has proved with some stunning deliveries since he moved to the club in January.

He scored with his very first touch in the Hoops, a free-kick at Pittodrie. And Robson has maintained his lethal deliveries, most recently with the penalty which defeated Rangers last month and the corner which set up the winner for Georgios Samaras at Motherwell last weekend.

Robson reckons there is capacity for both him and Naka to share the dead-ball duties, but knows that no team can afford to carry players just to contribute when the whistle blows.

Every one of the 11 men selected by manager Gordon Strachan has to be doing their bit for the entire 90 minutes, and Robson believes Nakamura - for all his skills - is, like him, more than willing to put in a shift.

He said: "Naka is one of the best free-kick takers in the world. There is no doubt about that.

"Look at his corners, free-kicks and crossing. It's exceptional.

"But he's also got more to his game. He's a fit guy, he works so hard for the team and he's great to play alongside."

With Robson taking Celtic corners on the right, whipping them in with his left foot, and the Japanese international firing them in with pace and accuracy from the left, defined set-piece roles have been established.

Robson said: "I can help Naka out with the corners, and vice versa.

"It's good to have that mix and we are both comfortable with the way that things are working out."