All professionals can knock in long reds and make big breaks off them but nobody does it quite like Ronnie O'Sullivan.
He has an aura about him, a style of play which makes him intimidating. He intimidated Neil Robertson, himself usually so mentally strong, yesterday afternoon and by the time the Australian had regained his composure it was too late.
O'Sullivan is now well placed to win his fourth world title but although it is day 13 of 17, we are only actually halfway through the tournament in terms of frames won.
The four semi-finalists have each won 36 frames but the eventual champion will need to win another 35.
Logic may dictate that O'Sullivan wins it from here but it hasn't been a logical tournament.
If it was, Ali Carter wouldn't be in the semi-finals after his frustrating season in which ill health has affected his form.
But Carter is a great fighter and he held off young Jamie Jones well to reach a third Crucible semi.
His match against Stephen Maguire is likely to be a good, competitive affair. Both of these players wear their hearts on their sleeves and are prepared to dig in for the fight.
These are really long matches now: four sessions with plenty of time for the psychological momentum to shift.
Maguire was here once before in 2007 where his 14-10 lead over John Higgins was overturned into a 17-15 defeat.
He will want to make amends for that and is playing his best Crucible snooker since 2008.
Matthew Stevens hadn't shown much form coming into the championship but is through to his sixth Crucible semi-final. His defeats in the other three were all close, as were his two world final losses.
It's nine years since he's beaten O'Sullivan in a ranking tournament so it doesn't bode well.
But it's been an unpredictable World Championship so there's no reason to expect it to go to any script as we enter the final strait.