Ronnie O'Sullivan began his pursuit of a record-extending eighth UK Championship title with a 6-2 win over Anthony McGill in York.
O'Sullivan won his first title at this event in 1993 when he beat Stephen Hendry 10-6 in the final, and his most recent in 2018 when he defeated Mark Allen by the same scoreline.
The 47-year-old slipped 2-0 down to McGill but then reeled off six frames in a row to set up a second-round meeting with fellow Englishman Robert Milkins, who edged Thailand's Thepchaiya Un-Nooh 6-5.
Speaking to the BBC after his victory, O'Sullivan said: "I find the matches quite long and hard now.
"The more I play, if I win two or three matches in a tournament, you get used to it, but I find it harder to concentrate and have the hunger.
"Against someone like Anthony, it's not about playing well, it's about digging deep and out battling them. That's hard at my stage."
Reflecting on the 30th anniversary of his maiden UK title at the age of 17, O'Sullivan added: "You get to the point where you think, 'I'll just keep going as long as I can now'.
"At 35, I probably thought I was done and dusted because that is what usually happens, you don't win so much. But I've had my best 10 years. Every year is a bonus, and you appreciate it more. It's like having a second life."
Another veteran in 48-year-old John Higgins is also through to the second round following a 6-3 win over Joe O'Connor and will next face Zhou Yuelong, who dumped out three-time UK champion Neil Robertson 6-2.
Allen was the defending champion this year but lost 6-5 to Ding Junhui in a repeat of the 2022 final.