Ronnie O'Sullivan fought past Daniel Wells in his opening match at the UK Championship but signalled that he may be forced to pull out due to suffering pain from breaking his ankle before the tournament.
The four-time champion moved comfortably past the amateur Wells 6-2 with a high break of 88, but was forced to wear a protective brace and looked in genuine discomfort throughout the match - resting his foot on a stool when not at the table.
O'Sullivan suffered the injury whilst running earlier in the week and warned that he will withdraw from his second round match with Peter Lines on Sunday if the injury doesn't improve.
"I wanted to see what happened. I was hobbling about and I can't get on a shot properly. If it doesn't improve I am not sure I will play my next match," O'Sullivan told BBC Sport.
Elsewhere, defending champion Neil Robertson breezed past Joe O'Connor 6-0 while Ruhr Open champion Shaun Murphy fought back from a 3-1 deficit against James Wattana to win 6-3. Robertson will face either Kyren Wilson in round two, with Murphy to meet Robin Hull, after the Finn battled past Thepchaiya Un-Nooh 6-5.
Ken Doherty turned in arguably the performance of the championship so far with a 6-2 victory over Mitchell Mann that included three century breaks. The three-time runner-up will play Michael White next after the Welshman saw off Cao Xinlong in similar 6-2 fashion.
Two-time Mark Williams opened his tournament with a convincing 6-1 triumph over Steven Hallworth, the highlight being a 101 break in frame three. Jimmy Robertson secured a 6-1 win over Zhou Yuelong to set up a last 64 tie with Williams.
World number six Mark Allen overcame Eden Sharav 6-2 to book a match with Belgian youngster Luca Brecel, who dropped just one frame against Noppon Saengkham , making a high break of 103.
CARTER SUFFERS COMEBACK LOSS
However Allister Carter suffered a 6-5 to China's Zhang Anda in his first ranking tournament since returning from lung cancer. The Essex player led the match 5-3 but a good fightback from Zhang which contained a century in frame 10, took him over the line in a deciding frame. Zhang's next opponent will be Rory McLeod who beat Ian Burns 6-2.
Stephen Maguire and Yu Delu will also clash in the second round, after 6-2 wins from both knocked out Lu Ning and Oliver Lines respectively.
Marco Fu, a finalist in 2008, began with a 6-4 victory over Qatar's Ahmed Saif. Lu Haotian edged out countryman Cao Yupeng by the same scoreline, and moves on to play Fu in the last 64.
Liam Highfield 6-3 Jamie Jones
Mark Davis 6-2 Jak Jones
Jack Lisowski 6-1 Chris Melling
Liang Wenbo 6-3 David Grace
Mark Joyce 6-2 Ratchayothin Yotharuck
David Gilbert 6-4 Elliot Slessor
SECOND ROUND TO BEGIN ON SATURDAY
The tournament will now take a one day hiatus, with the second round, and the televised stages beginning on Saturday.
Ding Junhui plays crowd favourite Jimmy White, John Higgins takes on Jamie Cope, and 2011 champion Judd Trump meets Aditya Mehta in the pick of Saturday's ties.