Dott, who had earlier overcome Andrew Higginson and Matthew Stevens, progressed at the expense of the Welshman.
Former world champion Dott will play Northern Ireland's Mark Allen in the last-16 after Allen beat Peter Ebdon of England 4-2 in the third round.
Last 16 matches:
MARK SELBY v PAUL S DAVISON
MARCO FU v MICHAEL WHITE
ALLISTER CARTER v JOHN HIGGINS
JOE PERRY v JACK LISOWSKI
ALFIE BURDEN v NEIL ROBERTSON
THEPCHAIYA UN-NOOH v ANDREW PAGETT
GRAEME DOTT v MARK ALLEN
BEN WOOLLASTON v TOM FORD
Final third round results:
MARK SELBY 4-0 RYAN DAY
PAUL S DAVISON 4-3 CHRIS NORBURY
MARCO FU 4-2 JIMMY ROBERTSON
JOHN J ASTLEY 1-4 MICHAEL WHITE
BARRY HAWKINS 2-4 ALLISTER CARTER
RICKY WALDEN 1-4 JOHN HIGGINS
ANTHONY HAMILTON 3-4 JOE PERRY
MATTHEW SELT 0-4 JACK LISOWSKI
ALFIE BURDEN 4-1 MARK KING
NEIL ROBERTSON 4-3 KURT MAFLIN
THEPCHAIYA UN-NOOH 4-3 TIAN PENGFEI
ANDREW PAGETT 4-2 STUART BINGHAM
MARK WILLIAMS 2-4 GRAEME DOTT
MARK ALLEN 4-2 PETER EBDON
DECHAWAT POOMJAENG 1-4 BEN WOOLLASTON
KEN DOHERTY 0-4 TOM FORD
