Extra time is under way.

Chris Waddle
BBC Radio 5 live at Anfield

"Liverpool have upped the tempo and have a little bit more about them. Both teams are feeling the pace - this could go anywhere."

The bottom line to all of that, of course, is that if Stoke score once in extra time, Liverpool will have to score twice to progress.

If Liverpool score the first extra-time goal, Stoke would only need one in reply to go through.

Nice and clear?

A reminder, as we head into extra time, that we're looking at penalties if the score stays as it is. 

And here's what the official rulebook, external says about away goals in extra time:

Rule 13.5: In the Semi-Final ties, if the aggregate score is level at the end of the second game an extra half-hour shall be played. If the aggregate scores are still level at the end of extra time the tie shall be decided by goals scored away from home counting twice. If the teams remain equal after this procedure the tie shall be determined by the taking of kicks from the penalty mark in accordance with the Laws of Association Football. 

We need another 30 minutes to separate these two.

Image source, Reuters

Image source, Reuters

Charlie Adam whips it to Peter Crouch at the back stick, but the ex-Liverpool man heads over.

Another Stoke corner.

Charlie Adam pumps it in low - that caught everyone by surprise, including Jon Walters. Stoke do manage to win a corner, mind.

Image source, Reuters

Liverpool corner... cleared, Stoke break through Ibrahim Afellay who wins a free-kick out wide. On Peter's head?

Four minutes of time added on, or we go to extra time.

Andy Miller: Two hands in the air = a signal to where corner is intended, eg. 1 hand near post, 2 hands back post. Still need to deliver

Christian Benteke drives forward, but realises he won't get any change out of Philipp Wollscheid and instead checks inside and plays a woeful pass to surrender possession. Hmmm.

Chris Waddle
BBC Radio 5 live at Anfield

"Lucas has gone to centre-half which is strange since it looks like he's feeling the pace. I still think he'll be able to keep up with Peter Crouch."

The Kop screams 'handball' when a cross thunders into the arm of Erik Pieters. Nothing doing. It was behind him and he had little chance to do anything differently.

Image source, Getty Images

Ash: This is Liverpool. Liverpool frustrate. They win once but lose next. Consistently inconsistent. Don't be like Liverpool.  

We won't get the pleasure of seeing Kolo Toure step up to take the winning penalty. He's replaced by Joe Allen. Or the Welsh Pirlo, as he now goes by.

Image source, Reuters

Ryan Lloyd: Liverpool are fools if they sell Benteke. Very frustrating player, but he's young and there's so much there to work with

Roberto Firmino is dropping deep to try and influence play. He gets the ball in a central position and takes aim, but it's nowhere near forcing Jack Butland into a save. If anything, it's more troubling for Jack in Row F.

The problem we have here, ladies and gentlemen, is that these two teams are incredibly well matched. We could be heading for extra-time.

Image source, Reuters

Chris Waddle
BBC Radio 5 live at Anfield

"All of the second half Marko Arnautovic has been grabbing his back or grabbing something."