Luke Littler has a snarl on his face as he crashes in a 180 - and then another!

Leaves 42 for an 8-5 lead - and takes it out. Three straight legs, now three legs from the title.

Luke Humphries knows he's in trouble. Luke Littler has really put his foot on the gas in the past two legs.

'Only one Luke Littler' echoing around London.

He almost takes out 167 in the next leg, just missing the bull.

But it matters not, he nails double 10 to move two legs ahead with a break of throw.

Image source, PA Media

The atmosphere in this arena is off the scale.

That is one of the best things I've seen in a darting arena.

This is a rivalry we could see for the next 10-20 years.

What a moment.

Unbelievable!

He's a nine-dart machine, Luke Littler.

The O2 Arena goes mad and Luke Humphries shares a warm hug with his opponent.

Seven treble 20s, a treble 19 and double 12. Classic.

Image source, PA Media

There is nothing this kid and phenom can't do.

HE CAN!!!!

A best-of-21 has turned into a best-of-11.

And both players return with 180s! Littler with two straight... he couldn't?

Luke Humphries hits the green lipstick of the treble 19 three times in the same visit to register a superb 171 that breaks the back of leg 10.

The world champion lands double eight and we're level at the mini-interval.

Image source, PA Media

Luke Humphries will be the happier player if they go off level at the break.

Luke Littler will see this leg as a bit of a freebie.

Luke Littler absolutely rattling off the legs when he throws first.

Humphries has not had a sniff against throw in the last couple.

That was world class.

Sensational clutch double 18 finish from Luke Humphries with his opponent waiting on a double to break.

Locked level again.

The 17-year-old looks comfortable on his own throw - even hitting tops with 60 left to leave his favourite double 10.

And he shows why it's his favourite.

It is still very difficult to call. Neither have settled 100% for my liking.

Bit of a weird final, the odd bit of heavy scoring but plenty of nerves and some very uncharacteristic mistakes.

However, Luke Humphries calms himself down to land double 16 and hold throw.

Big leg this for Luke Littler after seeing that 2-0 lead evaporate.

And he takes it out in 15 darts with very little ado.

A bounce-out in leg four for Luke Humphries is a hindrance he can do without.

But Luke Littler busts 80 the exact same way Humphries did - hitting double 15 when going for double 10.

Littler misses two more darts at double - and Humphries hits tops.

The world number one shakes off that disappointment with a 180 and 123 in the next leg.

And he takes out 58 to break straight back, his accuracy at double top restored.

Image source, PA Media

A very sloppy visit on 76 from Luke Humphries is not punished by his 17-year-old opponent.

But goodness me, Humphries busts on double 15 when going for double 10 - what a mistake!

And Littler lands double five to go two legs ahead.