Just a bit of a dip from Luke Littler, though - he has two darts at double 20 to break the Cross throw but cannot take either.

Cross tidies up to level this important sixth set.

Losing that fifth set has not rattled the 16-year-old at all.

Smashes through the first leg of the sixth set in 12 darts.

Rob Cross replies next leg by kicking off with 180 and 141. Super stuff.

Luke Littler kicks off set six with a pretty paltry 59.

No matter, the world youth champ follows it up with an umpteenth 180.

Image source, Rex Features

Luke Littler cannot find double top with one dart for the set.

Rob Cross can find it! He's back within a set.

Off goes Voltage for a break, while his 16-year-old opponent stays on the oche to practice.

GG in DC: Watching BBC text updates from Washington, DC. Fully supporting The Kebab Kid!

Joe Gibney: 16-year.old Luke Littler the new in-running favourite for BBC SPOTY. Only 50 weeks to go.

Massive chance missed for Rob Cross, who fails with two chances at double for the set. Luke Littler punishes him, which has been the story of this semi-final.

The former champ must hold his throw in this decisive leg of set five or he will be 4-1 behind. 4-1 or 3-2? Massive difference.

Rob Cross backs up that break-back with a hold of throw, checking out on double four.

Big response from Rob Cross, as he takes out a 150 finish with double 15 and earns a fist pump from his teenage rival.

Is that the spark Voltage needed? He came from four sets down in the quarter-final against Chris Dobey, remember. Two sets behind is nothing.

"There's only one Luke Littler, walking along, singing a song, walking in a Littler wonderland," chant the Ally Pally crowd.

That's the chant reserved for 16-time champion and darting royalty Phil Taylor.

Which tells you something in itself.

Luke Littler looks unstoppable right now.

Torching the trebles, dishing the doubles - and he's broken the Rob Cross throw again in the first leg of set five.

Unbelievable from Luke Littler.

Rob Cross was on a nine-darter in that leg but Littler kept pace with him - and when Cross faltered at the end, the teenager pounced to take out double 16 and win the set.

The 16-year-old is three sets from the World Championship final.

Image source, Getty Images

Rob Cross holds throw to take this fourth set into a decisive leg.

And Voltage hits six perfect darts - he's on a nine-darter... but the seventh arrow goes astray!

With Rob Cross sitting pretty on 42, Luke Littler takes out a 149 finish.

Treble 20, treble 19, double 16. Darting perfection.

This lad is special.

Huge hold for Rob Cross, who eventually finds a double in the red lipstick of the outer eight.

Will that settle the 2018 champ?

'The Nuke' is exploding right now.

He's leaving Rob Cross in his wake.

Storms to the opening leg of set four - and a 180 in the next leg raises hopes of another break.