Ronnie O'Sullivan beat Stephen Maguire 6-4 to set up a fascinating Masters final against Ding Junhui on Sunday.
O'Sullivan was in typical erratic form at Wembley Arena
Both O'Sullivan and Maguire looked out of sorts, but the former found his form at the right time with breaks of 130 and 69 to clinch the last two frames.
Chinese star Ding, who won a wildcard tie to qualify for the event, secured a fine 6-2 victory over Stephen Hendry.
Ding was 3-1 ahead before Hendry fired in a break of 129 but Ding won the next three and had a 128 break of his own.
The 19-year-old Ding, speaking through his translator, said: "I've not reached my best form yet, but I will try to play well in the final.
"It's always difficult to beat Stephen here. He always looks very comfortable. But I'm delighted to have won. I'm very happy, although I want to play better."
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Hendry, who has won the Masters title six times, praised Ding's ruthless consistency, saying: "The best compliment I can give him is that there's only two or three players where you don't think you'll get back to the table.
"If Ding's going to keep playing like that, then he's going to be a top four player for the next 10 to 15 years."
Conversely, O'Sullivan was erratic and visibly frustrated after edging his way past an even more profligate Maguire.
The Scot, who is still breaking in a new cue, produced a series of inexplicable misses to let O'Sullivan in on numerous occasions during a scrappy contest.
However, O'Sullivan rarely looked at his best either and, somehow, Maguire fought back from 3-1 down to level at 3-3 and then 4-4.
But O'Sullivan's class told in the end and breaks of 76, 88, 130 and 69 helped him into the final.
"I'm so embarrassed," admitted O'Sullivan, "I thought everyone was laughing at me. Playing like that, I'll get beat in the final.
"That's a big loss for Stephen. He must have been playing as badly as he possibly could to get beat. I didn't think he could play as badly as that."
Maguire agreed, saying: "It was embarrassing really, that's all I can say. He didn't even deserve to win it either.
"I still can't believe how badly I played. I should have got beat 6-0. It was a shame for the spectators, because the standard was not very good."