Raymond van Barneveld won the best match of the World Championship so far with a 4-3 victory over Ronnie Baxter.
The Dutchman was taken all the way by the 'Rocket' before winning the deciding set in a tie-breaker 6-5.
The man from Lancashire had two darts to reach the quarter-finals in the 11th leg but missed both attempts at double eight.
That gave the five-time world champion his chance and he duly took it, taking out 60 with two darts to stay in with a shout of retaining the title he won in 2007.
And this match may inspire him - 'Barney' won the title in Purfleet two years ago in a similar tie-breaker against Phil Taylor in the final.
Van Barneveld told Sky Sports: "I am a very lucky man today, I think. Maybe Ronnie deserved to go through but it is all about doubles."
Baxter added: "The man who hits the winning double is the man who goes through and that's it, simple as that. I didn't. I had two chances, missed it. All fairness to Raymond, simple 60, twenty, double top."
Van Barneveld will face his fellow countryman Jelle Klaasen in the quarter-finals.
Former BDO world champion Klaasen beat Andy Hamilton 4-1 despite 11 maximums from the 'Hammer'.
The Dutchman had yet to lose a set in his previous two matches at Alexandra Palace but after taking the first set 3-2, he lost the second by the same scoreline.
The first break of the darts did not arrive until the third set and it went the way of Klaasen as he won the fourth leg against the darts to lead 2-1 in sets.
Hamilton started the fourth set with an 11-dart leg but that was as good as it got for the man from Stoke as Klaasen won the next three legs to lead 3-1.
Hamilton broke Klaasen's throw for the first time in the match at the start of the fifth set and after losing the next two legs, levelled at 2-2 with a 14-darter before missing four darts at a winning double.
Klaasen punished him for that, hitting double 10 to reach the last eight.
The final match of the evening saw world No3 James Wade sweep past another Dutchman Vincent van der Voort 4-0 in less than an hour without breaking sweat.