Judd Trump says Stephen Maguire should have been one of snooker's all-time greats but has underachieved due to a lack of desire and dedication.
The pair are poised to meet on Wednesday in the last four of the Coral Tour Championship in Milton Keynes.
Experienced Scot Maguire hailed the best performance of his 22-year career after hitting a remarkable six centuries during Saturday's sensational quarter-final win over Neil Robertson.
World champion Trump was dazzled by that stunning display but criticised his upcoming opponent's overall approach to the sport and failure to realise his true potential.
"It's all mental really, snooker. You've got to have the talent, you've got to have the dedication and for me he's kind of missing two of the three of them," Trump said of 39-year-old Maguire.
"I think mentally he's not strong enough and he probably doesn't work hard enough.
"You see the players that work hard and enjoy their success; Mark Selby's probably the main guy, he's not the most talented but the way he's worked hard, and Ronnie (O'Sullivan) works hard at it.
"He just doesn't seem to want it as bad as some of the other players, including myself, and that's probably a big part of it.
"If he dedicated himself, five, six hours a day every single day, he would definitely be in the top four or top five in the world, without a doubt to me. He's that good when he wants to be.
"He should have been one of the best players of all-time and he's certainly underachieved in my eyes."
Trump lifted the world title last year for the first time by beating John Higgins in Sheffield and in March became the first player to win six ranking titles in a single season.
The 30-year-old believes Maguire – who has won five major ranking tournaments, including the 2004 UK Championship, across his career – could yet become a Crucible champion but warned time is running out.
"As you get older the self-belief is harder and harder to get back and he's going to struggle because some of these up-and-coming players have so much self-belief and when you keep getting beat and you keep getting knocked it's hard to come back from that," said Trump. "He's certainly someone who could win the world championship, if he wants it badly enough. "If he's willing to put the work in, he's certainly one of the players that has a chance. "He's someone that I enjoy watching in and amongst the balls when he's got his head on right. "Against Neil you could just see it in his eyes, he just wanted to make it, ton after ton, and there's only a handful of players that could have done that."
