Ronnie O’Sullivan overcame a dizzy spell to thrash Marco Fu 6-0 and reach the quarter-finals of the Dafabet Masters at Alexandra Palace.

O’Sullivan is seeking an eighth Masters title, and made three century breaks during the opening four frames, with Fu failing to pot a single ball before the interval.

While the 42-year-old defending champion showed compelling form to clinch victory, he said afterwards that he was under the weather.

O’Sullivan said on BBC2: “To be honest with you, I was really struggling. I don’t know if I have got a virus or something and I just feel very dizzy.

“I was just playing off instinct. I was thinking, ‘Don’t stop, just pot balls’. I was really quite struggling and have been like that for the last five or six days.

“I don’t feel ill, I just feel dizzy. I think it is maybe a lack of magnesium or something, that is what my nutritionist told me.

Ronnie O'SullivanRonnie O’Sullivan felt far from his best but still put on a stunning performance at the Masters (Adam Davy/PA)

“I have been eating well for the last four months, maybe I have overdone the exercise when I have been at home and made myself a bit ill.

“I know I can get through it, I still feel good physically and you just have to do a job.”

In Tuesday’s late match, Kyren Wilson battled past Barry Hawkins 6-4 to secure his place in the last eight.

Hawkins, the world number seven, opened up with a break of 131 and then 120 in frame three to lead 2-1.

Wilson, though, recovered to move in front himself with a run of 109 and another ton took frame seven.

Although Hawkins levelled the match at 4-4, Wilson, ranked at 14 in the world, produced two more half-century breaks to book his quarter-final spot against Mark Williams.

O’Sullivan, meanwhile, will play Northern Ireland’s Mark Allen for a place in Saturday’s semi-finals.