Littler breakspublished at 22:16 British Summer Time 26 July
Littler 3-6 Rock
If a nine-darter is going to get you going, what is?
Luke Littler breaks with a 14-darter after Josh Rock misses two at double 19.
World Matchplay semi-finals in Blackpool
Luke Littler defeats Josh Rock 17-14 to set up final against James Wade
James Wade beats Jonny Clayton 20-18 in epic encounter
Littler v Wade in Sunday's final at the Winter Gardens (20:00 BST)
Get Involved: #bbcdarts, WhatsApp on 03301231826 or text 81111 (UK only, standard message rates apply)
Sam Drury and Ben Ramsdale
Littler 3-6 Rock
If a nine-darter is going to get you going, what is?
Luke Littler breaks with a 14-darter after Josh Rock misses two at double 19.
Littler 2-6 Rock
Wayne Mardle
Former World Championship semi-finalist on Sky Sports
That is the second best leg you will ever see in your life!
Littler 2-6 Rock
LUKE LITTLER HAS HIT A NINE-DARTER!
That is absolutely outstanding - from both players!
There were 15 perfect darts in that leg - it's just that Littler threw first so Josh Rock didn't have the chance to go for his nine-darter.
Stunning, just stunning. Treble 20, treble 17, double 15 for Littler to finish off his perfect leg.
Littler 1-6 Rock
Comfortable hold for Josh Rock.
Double six for a 12-darter.
Littler 1-5 Rock
Wayne Mardle
Former World Championship semi-finalist on Sky Sports
He has won his first leg but that was odd. That was poor board management, there is no doubt about it.
Littler 1-5 Rock
Luke Littler is up and running.
He is a long way clear but then gets a bit slack before cleaning up his own mess with double 16 for a 14-darter.
Littler 0-5 Rock
There is a long way to go here and if there is anyone you'd back to recover from this deficit, it's Luke Littler.
But if Josh Rock keeps playing as he has, it is going to be incredibly tough for the teenager.
Littler 0-5 Rock
We were told to expect fireworks in this one - and so far it's Josh Rock providing them.
It's two 180s apiece but Rock has seven 140-plus visits to Luke Littler's none and averages 100.2 to the world champ's 92.91.
Littler 0-5 Rock
Josh Rock gave Luke Littler every chance in this leg... but still the world champion can't get himself on the board.
Rock dominated the leg but missed six at double.
That gave Littler a chance he could barely have expected and perhaps that is the issue as darts at tops and double 10 miss their mark.
Rock gets it done on double two eventually. What a start!
Littler 0-4 Rock
Dan Dawson
Commentator on Sky Sports
It was clear when Josh Rock turned up that he was a great talent with massive potential but he is really delivering on it this year.
Littler 0-4 Rock
Wayne Mardle
Former World Championship semi-finalist on Sky Sports
You do dream of making good starts in big matches. I think this would go down as a good start for Josh Rock.
Littler 0-4 Rock
What is going on here?
Luke Littler looked to be home and dry in this leg but misses three darts at double to let Josh Rock in.
Rock himself misses tops but finds the bed of double 10 and he's 4-0 up!
Littler 0-3 Rock
After two brilliant legs, this one is a little more pedestrian but Josh Rock will take it.
The 24-year-old needs 18 darts to hold but does so by hitting tops.
Luke Littler is up against it early on.
Littler 0-2 Rock
It's fair to say that Josh Rock has come out firing!
The Northern Irishman breaks the Luke Littler throw with a 12-darter.
A 180 to start the leg and brilliant scoring before hitting double eight to finish.
Expect a Littler response pretty soon...
Littler 0-1 Rock
Don't expect much time to think in this one, both these two play at a remarkable pace. So wish me luck...
Anyway, Josh Rock takes no time to settle in. An 11-dart hold of throw sealed on double top.
Littler 0-0 Rock
Here we go! Josh Rock to throw first.
Let's. Play. Darts.
Littler v Rock
Littler v Rock
Josh Rock started the tournament with a bang as he averaged 104.32 and hit a 167 checkout as he knocked out 14th seed Ross Smith.
That was just the start as the unseeded 24-year-old proceeded to beat three-time world champion Michael van Gerwen in the second round, coming back from 5-1 to do so.
Rock saw off another former world champion in the quarters and again posted a 104 average to get the better of Gerwyn Price.
Littler v Rock
Only four players have ever achieved darts' Triple Crown - World Championship, Premier League and World Matchplay.
Gary Anderson, Phil Taylor and Michael van Gerwen were joined in that exclusive club by Luke Humphries when he won the Premier League in May.
Two months later and Luke Littler is hoping that turn that quartet into a quintet.
It would be a remarkable achievement for the 18-year-old in just his second year since earning his Tour Card.
Having won the Premier League last year before adding the World Championship in January, he is two wins away from completing the set with the Matchplay.
With triumphs at the Grand Slam and UK Open, he already has five major wins to his name.
If number six comes this weekend, it will be a particularly special achievement.
Littler v Rock
Luke Littler is into his first Matchplay semi-final but it has not been plain sailing for the world champion.
After blitzing past Ryan Searle in the first round, averaging 108.92, Littler has been pushed all the way in the past two rounds.
He had to come from 7-2 down to beat Jermaine Wattimena before holding off a brave fightback from Andrew Gilding in the quarters.