Welshman Lee Walker suffered fade-out as David Gray reached the quarter-finals of the Embassy World Championship for the first time in Sheffield on Monday afternoon.

Former Scottish Open champion Gray needed just an hour to complete a 13-5 victory after resuming the penultimate session 11-5 in front.

"I'm surprised I won by such a margin considering I wasn't firing on all cylinders," said the world number 13 from Surrey.

"I was too calm before the first session; it felt like I was just going to practice," added the 25-year-old.

"It wasn't my greatest performance but a win is a win. And I felt comfortable throughout the match.

"Surprisingly for me I won all the scrappy frames but I will need to score a lot heavier if I want to get any further."

Gray could find himself playing Dott for a place in the semi-finals providing Graham Dott does not squander a 10-6 lead going into his last session with 1998 champion John Higgins.

"To be honest there were always going to be a few shocks in the tournament. You are never sure what you are going to get in snooker at the moment."