Lisowski made breaks of 60, 82 and 100 as Williams only made 21 points before the world number three clicked firmly into gear with knocks of 96 and 98 helping him set up a semi-final with Noppon Saengkham, who floored Xiao Guodong 5-1 in the final quarter-final in Yushan.
Marco Fu was unable to recreate his form from his 5-2 win over Robert Milkins in the last 16 as the Hong Kong player suffered a 5-3 quarter-final loss to David Gilbert.
World Open
Williams pulls off World Open comeback to win title
12/08/2018 AT 12:23
Fu had looked back towards his best in beating Milkins, but struggled to get going against Gilbert on Friday.
Watch this event on Eurosport Player
And the 16th-seed's defeat means he will now not be able to qualify for next month's high-profile Shanghai Masters.
The best-of-nine-frame win for Gilbert (known in snooker's inner circle as 'The Angry Farmer') sees him reach only the second ranking event of his career, but the 37-year-old was well worth his victory, with a break of 122 in the fourth frame the stand-out moment of his match.
Barry Hawkins also reached the last four on Friday with a 5-3 win over Gary Wilson.
The Hawk raced into an early three-frame lead, but was made to work for his win, with a break of 101 in the eighth frame sealing his spot in the semis against Gilbert.

World Open Results

  • David Gilbert 5-3 Marco Fu
  • Barry Hawkins 5-3 Gary Wilson
  • Noppon Saengkham 5-1 Xiao Guodong
  • Jack Lisowski 3-5 Mark Williams
Watch this event on Eurosport Player
World Open
Williams sizzles to coast into World Open quarter-finals as Selby crashes out
09/08/2018 AT 10:41