LONDON - Ronnie O'Sullivan came from behind to edge Mark Selby 17-16 on Friday, reaching the final of the Snooker World Championship for the seventh time.

O'Sullivan defeated China's top player Ding Junhui 13-10 to book a quarterfinal berth before he came from 8-4 down to defeat Mark Williams 13-10

Five-time world champion O'Sullivan will play against first-time finalist Kyren Wilson on Saturday and Sunday over a possible 35 frames, as world number eight Wilson nosed out qualifier Anthony McGill 17-16.

Over the three-day semifinals, O'Sullivan took advantage in the first session in 5-3 but lost four frames in a row after the start of the second session. The Rocket attacked in style to come from 13-9 down to level at 13-13, then was one frame from loss while three-time world champion Selby leading at 16-14.

ALSO READ: O'Sullivan reaches Snooker World Championship semis

In the deciding moment, the 44-year-old O'Sullivan amazingly took the 31st frame with a break of 138, the highest of the match, before finishing the trilling semifinal 17-16.

O'Sullivan defeated China's top player Ding Junhui 13-10 to book a quarterfinal berth before he came from 8-4 down to defeat Mark Williams 13-10.

READ MORE: China's Ding loses to O'Sullivan at Snooker World Championship

His last appearance in the final at Crucible was in 2014 when he lost to Selby.