Aidan O'Brien believes Ruler Of The World's failure to act on the Tapeta surface was to blame for his disappointing display in the Dubai World Cup.

Last year's Epsom Derby winner was among the leading contenders for the world's richest race, but came home 13th of the 16 runners under the trainer's son Joseph at his first start on an artificial track.

"We didn't know whether he would handle the surface and it looks like he probably didn't," O'Brien said.

"Joseph said he was grand until he came off the bridle and then he was all at sea."

Each of O'Brien's six runners on World Cup night failed to finish in the frame although both Giovanni Boldini and Magician ran with credit.

Giovanni Boldini came home well to grab fourth in the UAE Derby, while last year's Breeders' Cup Turf winner Magician encountered traffic problems on his way to finishing sixth, beaten three lengths, in the Sheema Classic.

"Ryan (Moore) was delighted with Giovanni Boldini," O'Brien said.

"He ran a very good race. He definitely gets a mile but I'm not sure if he'd get further.

"He'll probably go for one of the Guineas.

"Magician ran well. It was a bit messy on the first bend, we were always going to drop him out, though.

"We might train him for the Prince of Wales's Stakes at Royal Ascot."