Seven-time world champion Ronnie O'Sullivan suffered a 4-0 defeat by Shaun Murphy at the Champion of Champions tournament in Leicester.

O'Sullivan, who has been struggling for form, was playing for the first time since losing to Ka Wai Cheung at the Northern Ireland Open last month.

The 50-year-old found himself 2-0 down against Murphy, who knocked in a 68 in the second frame.

Murphy made a 41 break to take the next frame before taking a tense fourth frame 61-42 to secure victory and a spot in the last eight.

He will play the winner of the other Group Three match between world champion Wu Yize and Chang Bingyu.