Scarlets are keen to show they're not out of this game yet, and Leigh Halfpenny kicks over their penalty to reduce the deficit to five points.

Hooker Ryan Elias is on for the Scarlets in place of Marc Jones.

Seb Davies comes on for Cardiff Blues as James Ratti goes off holding his arm.

Gareth Davies, keen to make amends for his earlier yellow card, wins a penalty on Blues' 10-metre line.

Scarlets have started the second-half brightly considering their numerical disadvantage.

Cardiff Blues look to attack straight away now they have the man advantage, but Matthew Morgan's pass to Hallam Amos is forward and Scarlets will have a scrum near half-way.

Jarrod Evans gets us back underway at the Cardiff City Stadium.

Dafydd Pritchard
BBC Sport Wales at Cardiff City Stadium

What an eventful and entertaining first half.

As I hoped would be the case before kick-off, this has been a welcome antithesis to the dross of previous festive Welsh derbies.

With Scarlets having to navigate the second half with 14 men, this match is fascinatingly poised.

The Blues were looking to add to their advantage in the closing seconds of the half but the 14 Scarlets hold firm.

Cardiff try the driving maul from the line-out three times, as they say, "If at first you don't succeed, try and try again".

But it all came to nothing, and the Scarlets win the ball back from a knock on and the first half comes to an end.

On his return Wales full-back Liam Williams has been shown a straight red for his dangerous entry into the ruck.

Williams made no attempt to wrap his arms and his head made direct contact with Shane Lewis-Hughes.

After referee Craig Evans told Williams he would be sent off, the British and Irish Lions responded: "Going to start playing touch is it?".

That might not endear him to a disciplinary panel and the fact remains Scarlets will play the rest of the game with 14 men.

Image source, Huw Evans Agency

Referee Craig Evans wants to talk with the TMO after Liam Williams appears to go head-first into a ruck, making contact with Shane Lewis-Hughes' head.

Rey Lee-Lo is over in the corner but we will go to TMO to see if he was out of bounds beforehand.

Despite being a man down the Scarlets add an extra three points through the boot of Dan Evans and there is just a point in it.

A few more heated words are exchanged between the sides, Cardiff Blues' number eight Josh Turnbull and Scarlets wing Liam Williams at the centre of things.

There is definitely more of an edge to this match than the earlier one at Rodney Parade.

Steff Evans is acting scrum-half while Davies runs down the remainder of his yellow card.

Scarlets win a penalty and there is a noticeable drop in tempo as the visitors look to slow down the match while a man short.

Scarlets prop Pieter Scholtz hobbles off and Javan Sebastian is on in his place.

The Scarlets are going through the phases, running down the time before Gareth Davies is allowed to return.

The men in red have another five minutes before they're restored to their full complement.

The Blues opt to take the points from the penalty, and Jarrod Evans makes no mistake this time as the hosts extend their lead.

Scarlets scrum-half Gareth Davies is sent to the sin bin for a cynical deliberate knock on in the tackle.

The one thing the Dragons-Ospreys game didn't have earlier was any handbags, but that last phase of play ended with a few pockets of Blues and Scarlets players exchanging words, let's say.