The American, 34, won 6-2 6-3 to pass Roger Federer in the all-time list of matches won at the tennis majors.

She moves on to the quarter-finals, where she will face Romanian fifth seed Simona Halep, who beat Spain's Carla Suarez Navarro 6-2 7-5.

"It's a huge number," Williams said of her record 308th win.

"I think it's very significant actually. I definitely never thought I would be playing still. Now I don't really see when I'm going to stop.

"I'm just enjoying these moments out here, getting to break records that I didn't even know existed or I didn't even know was possible.''

Halep has lost seven of eight matches against Williams but hopes that will at least keep the pressure off in their quarter-final.