Safety play helps mark Allen oust favourite Neil Robertson

The match was a curious mixture of classy break-building and scrappy spells, Allen making five half-centuries to his opponent's four but the pair still requiring more than three hours to complete the ten frames.

Allen will next face the winner of the clash between Peter Ebdon and Marco Fu.

Allen credited his improved tactical game with seeing him into the semi-finals.

"I think it was my safety that got me through today," he said. "I've taken a bit of time, and started watching people who have been doing well."

Robertson was gracious in defeat, backing Allen to go on and win the event. The Australian said: "I played pretty well. He played two really good frames towards the end. I felt really good today. My long potting was good.

"I can't really fault my performance today, and say I played badly. Mark played really well today, and in my opinion he is now the favourite to win the tournament.

"It depends on how he plays in the role of favourite, because sometimes that can bring extra pressure."