Three-time world champion Mark Williams will replace Zhao Xintong at the Hong Kong Masters after the UK title holder tested positive for Covid-19 on Wednesday.
Williams was next in line to compete at the eight-player invitational event and takes Zhao's spot against Neil Robertson on Friday afternoon at the city's Hong Kong Coliseum.
A record crowd approaching 9,000 fans are expected to watch each match of the elite event with Judd Trump's quarter-final with John Higgins being moved to Thursday night in Hong Kong (12pm BST).
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Welsh icon Williams will face 2010 world champion Robertson in the tournament's third quarter-final on Friday afternoon (6.30am BST) in the chase for the £100,000 first prize.
"Williams was next in line for a place, as per the invitation criteria for the event, which was based on the world rankings at the conclusion of the 2022 World Championship," said World Snooker Tour in a statement.
"We wish Zhao a speedy recovery."
Tournament organisers had gained approval for the eight players competing to travel between their hotel and the Coliseum during the four-day event with several arriving less than 72 hours before the action breaks off.
Hong Kong's official Covid rules state that visitors must adhere to three days of quarantine with restrictions on movements. It is unclear when Zhao tested positive for Covid.
Breaching quarantine laws is a criminal offence, but overseas arrivals – including the world's top six players O'Sullivan, Judd Trump, Mark Selby, Neil Robertson, John Higgins and Zhao – had been granted an exemption to allow them to prepare for the tournament which runs between Thursday and Sunday live on Eurosport.

Revised Hong Kong Masters 2022 schedule (All times BST)

  • Thursday, October 6 - Quarter finals: Mark Selby v Marco Fu – 06:30; Judd Trump v John Higgins – 12 noon
  • Friday, October 7 - Quarter-finals: Neil Robertson v Mark Williams – 06:30; Ronnie O'Sullivan v Ng On Yee – 12 noon
  • Saturday, October 8 - Semi-finals: Selby/Fu v Trump/Higgins – 06:30am; Robertson/Williams v O'Sullivan/Ng – 12 noon
  • Sunday, October 9 – Exhibition match – 06.00; Final – 12 noon
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