In the end, he defeated Mervyn King 4-1 as he reaches this stage for the first time since 2014; in what was a great start to the post Christmas entertainment at the Palace.
Whitlock missed the bull for a 90 checkout but King couldn't finish off 102; despite that the Australian messed it up and King took an early break on double two.
King kicked off the leg on throw with a 180 and potentially set his sights on a nine-dart finish only for him to go outside the treble 20 on the 5th dart.
He was down to 104 and well ahead on his throw; he finished a 104 to go 2-0 up. Whitlock hit a 180 and left himself 58 on throw; King pressured with a 180 to leave himself 57 and he took the set in no time.
The Bradwell ace upped his average to around the 105 mark as he made it five legs without reply to go one away from a double quick time lead. Despite that Whitlock was quickly back into it forcing a deciding leg; in that decider King was well ahead on 96 but was pressured with an excellent 180.
King didn't get a shot from there and Whitlock used his lifeline to pin a 54 checkout to take a set back. Whitlock started the next set in similar vein; pinning a 68 checkout for the lead.
King stopped the rot of sorts holding his throw but the impetus was now on him to recapture that form which nearly saw him take a 2-0 lead.
He broke throw with an 81 checkout to retake the momentum. A 52 checkout after King missed the chance to win the set saw Whitlock send it to a decider in which he had the throw; he was suddenly looking likely to go 2-1 up in sets.
A 92 checkout saw him do just that; as he looked like he had the rub of the green in a game where King could so easily be 3-0 up in sets.
Whitlock doubled his lead in the third set; as it looked like he was about to take real control and go 3-1 up in sets. A 148 checkout saw him take this control and go one set away from the finishing line.
On a real important set where Whitlock started with the throw, King kicked off with a 180 and he romped to a two leg lead from there.
Despite that, Whitlock forced a decider and he had the throw in it; as he went towards the finishing line. Whitlock had darts for the match; but he missed the big 16 for a dart at double 20 for the set; Whitlock pinned double 10 to move through.
Click here for more information on the PDC World Darts Championship, which takes place at the Alexandra Palace between December 13 and January 1.
Simon Whitlock (90.94) 4-1 (89.51) Mervyn King
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