And here's their second from big Ben Murdoch-Masila...

Here's how Warrington scored their first try, courtesy of Joe Philbin...

St Helens can feel very aggrieved not to have scored first, however.

Replays showed Morgan Knowles grounded the ball from a low kick early on, but referee Robert Hicks chose not to check with his video referee.

If Warrington go on to win, I'm sure that'll be a big talking point.

A brilliant first half if you're a Warrington fan, and certainly not what most of the pundits expected.

The Wolves started as underdogs but have been clinical in attack and their two tries in quick succession have given them a handy half-time lead.

Image source, PA Media

Jonathan Davies
Former Great Britain international on BBC One

Warrington have done their game plan well, they know they have big ball carriers to cause damage by the try line.

When they've had pressure and momentum they've had to score tries and they have certainly done that.

Saints will have opportunities, so we really have a final now because the best side in the competition by far (St Helens) need find a few more gears and we all know it's in them.

A wonderful effort in defence by Warrington to keep St Helens out. That'll surely be that for the first half.

Declan Patton's misplaced kick gives St Helens a seven-tackle set to try to find a response to Warrington's two tries before the interval.

Midway through the set, there's a penalty for Saints 20 metres out and they'll run it again...

Ged Scott
BBC Sport at Wembley

How often does that happen in sport? A try turned down at one end, then the other team go straight up the other end and score. And then another too!

The only consolation for St Helens is that Warrington’s two tries have given them the chance of a breather, as the entire Saints half is now in shade. So it’s got to be less hot at that end.

Having said that, they’re still taking pitchside temperatures well in excess of 30 degrees. So it’s pretty darn hot wherever you are.

And the two hottest players on the pitch must surely be opposing wingers Josh Charnley and Regan Grace, who have been most exposed to direct sunshine down in the right corner of the Warrington half.

Injured Warrington Wolves half-back Blake Austin tells BBC One from the bench:

"We had to be good early and we've managed to do that.

"St Helens have been told they've got to show up to win. The longer we can hold them to zero and the more doubt creeps into their mind, I think."

Oh my, Lachlan Coote. Under no pressure, he drops a high ball and Warrington are in prime position to strike.

You could probably count the number of drops like that that he's made all season on one hand.

Warrington are on the prowl again but St Helens hold firm. That Joe Philbin try has given Warrington a huge lift.

But then Zeb Taia throws a forward pass early in the tackle count and they sacrifice possession again. This is very unlike St Helens.

Jonathan Davies
Former Great Britain international on BBC One

He spotted the gap and just went for it, that is a brilliant finish from Joe Philbin.

The St Helens defenders over-read that play.

And video referee Ben Thaler concurs with the on-field official.

Mark Percival's effort won't count as Zeb Taia lost the ball forward near the try line.

Meanwhile, Warrington captain Chris Hill is free to continue after coming through a head injury assessment - he's waiting to return to the action from the bench.

Saints hope they might have scored the first try of the game, but it's been sent upstairs to the video referee with a "no try" signal from Robert Hicks...

Image source, Rex Features

We're getting to the stage of the half when tired bodies, especially in these hot conditions, could start to make mistakes.

A couple of players are down receiving treatment and some vital fluids are being taken on board.

There's a bit of chaos as St Helens attack again. A couple of kicks, a couple of fumbles, a couple of collisions. Warrington survive.

Brian Noble
Ex-Great Britain coach on BBC One

Well it's hot, they told us on the sidelines it's hot, the game's going to get hot.

It's hot...

Jonathan Davies
Former Great Britain international on BBC One

Warrington have to keep their width because St Helens have got so much pace out wide, but they are struggling because of the quick play of the ball.