Paul Grayson
Former England fly-half on BBC Radio 5 Live

The frustration for Saracens is that Leinster had slowed the ball down and Brad Barritt just lost his cool. They were two metres out and patience was the order of the day.

Wonder what Owen Farrell's thinking so far? It's not been a dream start for Sarries.

Image source, Getty Images

Saracens are building an attack just a few metres out, but the whistle's gone.

There's a bit of French chatter between the referees. It seems Brad Barritt has come in at the side in the ruck and Leinster get the chance to clear their lines.

So 20 minutes played and just one penalty scored so far. Ugo Monye said this was going to be a physical game of chess and he's right so far. It's just too difficult to separate these sides.

Liam Williams is down holding his shoulder. I think it's the same one he injured during the Six Nations. He gets back up, hopefully it's not a serious problem.

Image source, Getty Images

Luke McGrath has some nerve. He burrows his way into the ruck, recovers the ball and clears it into touch.

But Leinster have knocked the ball on and give Saracens a scrum inside their own half.

It's a slow-starting attack though. It feels like Leinster have the upper hand in this game so far. Liam Williams brings things to life with a kick through and pins Leinster back just a metre out from their tryline.

Image source, AFP

Larmour impresses again. Sean Maitland goes in pursuit of another Ben Spencer box-kick but Larmour's grabbed it.

Alex Goode gets the ball off the scrum and tries to break free but is brought down by Luke McGrath.

But Jordan Larmour's picked it up and he's off! He's too fast for Alex Lozowski but knocks on. A glimpse of how dangerous the Ireland international can be if Saracens give him the chance.

Paul Grayson
Former England fly-half on BBC Radio 5 Live

Jerome Garces is allowing both teams a proper crack at the breakdown and we will see turnovers. The intensity of the game is terrific.

The ball pings back and forth between the two sides but now Garry Ringrose drops it. This one is a knock-on. Frantic stuff.

We have our first scrum of the game inside Leinster's 22. It doesn't budge at all but Leinster keep the ball safe. Luke McGrath puts up a clearing kick but it doesn't go far and Saracens attack again outside the 22.

Oops! Ben Spencer's offload hits Owen Farrell on the chest but Jerome Garces doesn't call a knock-on.

Paul Grayson
Former England fly-half on BBC Radio 5 Live

This is some game of chess...

The king has been knocked over already and we are going to Battleships. Both teams are absolutely going for this with ball in hand.

The ball comes back into the midfield and Alex Lozowski goes to a long ball out to Williams again but the Welshman has lost it forward.

This game looks as though it will live up to its billing so far.

Saracens send Billy Vunipola bulldozing into the blue wall. Alex Goode gives a lovely offload to Liam Williams who dances forward on the right wing. This is vintage Sarries.

Jordan Larmour tries a clever kick through but Saracens collect it.

Leinster's forwards power over the ruck and look to have regained the ball, but Jerome Garces isn't happy with their work and gives Saracens a penalty.

Paul Grayson
Former England fly-half on BBC Radio 5 Live

There are blue flags everywhere. It's a great kick by Johnny Sexton and it's clever play to take the lead.

Luke McGrath box-kicks again - the kick count is going to be high today I suspect - and Johnny Sexton gathers.

Leinster are up to Saracens' 10m line now.

Image source, Reuters

Instead, Leinster are awarded a penalty and World Rugby player of the year Johnny Sexton absolutely nails it.

The crowd is awash with Leinster flags.

Billy Vunipola charges down a kick! But Leinster had the advantage... Saracens were offside. Seemed like that could have been one of the 'magic moments' Mark McCall's been talking about. But not yet.