Ali Carter completed his journey from the brink of retirement to a place in the World Championship final as he inflicted a painful defeat on Stephen Maguire.

Essex cueman Carter was suffering so badly with Crohn's disease that he considered walking away from the tour. The World Championship would have been his last tournament but instead it could be the making of Carter.

The 32-year-old turned a 14-10 lead into a 17-12 triumph over Maguire, for whom the match appeared to be a miserable experience from start to finish.

Rarely did the run of the balls favour the Glasgow potter, who lost to John Higgins in his only previous Crucible semi-final five years ago.

Maguire also failed to produce the form which saw him send Stephen Hendry into retirement after a 13-2 quarter-final triumph, and when he lost a dramatic opening frame today his hopes effectively were over.

Carter, with a 21-point lead, was put in a clever snooker behind the black, which was by the side rail near the yellow spot.

Carter tried six times to strike the final red and failed, and on the final occasion referee Leo Scullion elected not to call a miss. Carter had been a whisker away from hitting the ball, so Scullion's judgement meant his fellow Glaswegian, by that stage three points ahead, had to play from where the white finished.

The double was on but the red wriggled out of the jaws. Carter produced an outstanding pot to the far left corner and soon took the frame.

Maguire's head dropped and he soon lost the next frame, Carter having an outrageous fluke red in the process. The red Carter was playing clipped off another and dropped in. Maguire could only laugh.

Maguire got to 56 in the next frame before missing a straight red to the centre pocket, but it did not cost him.

The Scot made it back-to-back frames, aided by a break of 53.

But once they returned from a mid-session interval, Carter leapt at an opportunity which presented itself after Maguire potted a long red but followed it into the pocket with the cue ball.

He rifled in a break of 70 and Maguire offered his hand.