Halfway point of the innings and Surrey very well set for a mammoth total it would appear.

Another Sangakkara six!published at 24.2 overs

24.2 overs

Surrey 177-1 (Roy 91, Sangakkara 39)

Second six for Kumar Sangakkara as he hammers Brett D'Oliveira's full toss over the fence and over cow corner.

Destructive hitting.

James Taylor
Ex-England batsman on BBC Test Match Special

I'm gonna say with this platform Surrey are looking at 400, on this surface, with this outfield.

If you've got another 15 to 20 overs of Jason Roy then the world's your oyster.

Daryl Mitchell back with ball in hand. Kumar Sangakkara sweeps for four and then has to dash for a quick single that might have been close with a direct hit.

Image source, Getty Images

This is an all-too familiar sight for Worcestershire at the moment. Jason Roy was seriously out of nick for England in the Champions Trophy.

He's looked in majestic form for Surrey so far.

Another tidy over by Brett D'Oliveira concedes just four runs.

Some power and destruction at one end and some patient, watchful batting at the other at the moment.

Jason Roy also tucks into Ed Barnard's opening over with a pull shot for four.

Surrey push the accelerator once again after a calmer period of late...

Six from Kumar Sangakkarapublished at 21.3 overs

21.3 overs

Surrey 156-1 (Roy 84, Sangakkara 25)

Another bowling change for Worcestershire as Ed Barnard comes on from the New Road End with his right-arm seamers.

Kumar Sangakkara clubs the first ball he faces from him for four into the offside to bring up the 150.

Next ball, it's a huge shot straight drive down the ground for six! What a shot that is...

Brett D'Oliveira into the action with his leg breaks for Worcestershire.

Nice bit of flight from him with his early deliveries, Roy and Sangakkara just taking a look at him to begin with.

Just the three singles.

James Taylor
Ex-England batsman on BBC Test Match Special

Moeen Ali's got a decent record against Kumar Sangakkara especially when the pitch is turning because he puts so many revs on it and bowls at a real good pace.

He can drift it into the left and then spin it away and that's the ultimate ball which he's bowled to Sangakara on a number of occasions.

Another tidy over from Moeen Ali to rattle through the deliveries and restrict the boundaries for Surrey.

Still a great platform though for them for a big total. Moeen's five overs have cost just 20 runs.

The players take a well-earned drinks break after 20 overs...

Another promising over from Josh Tongue who's plugging away on a line and length here for Worcestershire.

Kumar Sangakkara clips him into the leg side for three runs with a lovely elegant trademark shot.

Moeen nearly picks up a second wicket as England team-mate Jason Roy gets in a bit of a tangle trying to reverse sweep him.

Three for Sangakkara at the end of the over as Josh Tongue makes a good slide and stop on the boundary to save a run.

Moeen Ali is often the man for the big occasion. He's given Worcestershire some much-needed relief with the only wicket to fall so far.

A couple more wouldn't go amiss from a Worcestershire point of view. Surrey are well on top at the moment.

If the hosts are to win this, then Moeen will probably have to have a good day with the bat too.

Unlucky for Josh Tongue as a very decent ball from the right-armer goes for four off Jason Roy's outside edge.

That would've been down second slip's throat in a Test match for sure.

Kumar Sangakkara keeps ticking over with a pull through leg side. Things just a bit calmer in this game at the moment.

Another tidy over from Moeen Ali with just three singles from it.

Worcestershire dragging it back a touch now after the early fireworks.

Josh Tongue returns to the action with the ball for Worcestershire.

Nice return over as he concedes just a single from it, including a decent looking bouncer to Kumar Sangakkara to finish.

Kumar Sangakkara comes into this match having posted back-to-back centuries, recording 124 not out off 121 balls against Hampshire and 121 off 121 balls last time out versus Yorkshire Vikings in the quarter-final on Tuesday.

He's off the mark with a simple single, how many might he accumulate today?

Ebony Rainford-Brent
Ex-England batter on BBC Radio 5 live sports extra

Image source, Getty Images

That's a good ball from Moeen Ali, he just gave it a little bit of air.

It takes confidence on a wicket like this because you know batsmen might use their feet or open up. And he did open up, but there was a fraction of grip off the surface.

A good wicket!