Chelsea see off the corner, and counter quickly. Barca have it covered this time, but that is the danger for them.

The hosts have had 63% possession so far, which honestly is lower than might have been expected.

Aitana Bonmati gets involved for the first time, and immediately the Chelsea players are backing off in fear as she charges through the middle.

Bonmati lays off for Salma Paralluelo, whose shot is deflected over.

Image source, Reuters

Lauren James presses the Barca defence into conceding a throw in in a good attacking position for Chelsea.

It comes to nothing, although did serve to rile some Barca players who felt it was not a throw. Stephanie Frappart, our referee today, had to lay down the law to a couple of dissenters.

Pat Nevin
Former Chelsea and Scotland winger on BBC Radio 5 Live

Two or three times that Barcelona have gotten down the side, they have gotten into those dangerous positions at the byline and got the ball in but no chances have come from it.

Why? Chelsea have the bodies in there. The three centre backs has worked an absolute treat so far, that is exactly what Emma Hayes would have been hoping to see.

Image source, Getty Images

Emma Sanders
BBC Sport at Estadi Olímpic Lluís Companys

First look-in for Chelsea then with Johanna Rytting Kaneryd. The Barcelona fans to our left stopped banging their drums for a moment as Ingrid Syrstad Engen had to mop up.

Pat Nevin
Former Chelsea and Scotland winger on BBC Radio 5 Live

That chance will make Johanna Rytting Kaneryd feel very confident.

She is up against Fridolina Rolfo today, and that was the first chance she had to run at her and she had the pace on her.

She now knows 'Ok one on one I can do her for pace, get me in behind.'

Ona Batlle, who English fans know well from her impressive time at Manchester United, gets forward from right back for the first time.

Chelsea get the numbers back to block off her avenues into the area.

A first attacking sighter for the visitors, as Johanna Rytting Kaneryd is played in over the top on the right.

Barcelona manage to shepherd the ball away, but encouragement for Chelsea.

Emma Hayes, wearing a very smart blue suit today, issues instructions on the touchline.

She will have expected her team would have been under the cosh from the off, and that is how it has transpired.

Image source, Reuters

Caroline Graham Hansen is on a tear in these early stages. She streaks past Niamh Charles down the right, before her cut back is cleared behind by Jess Carter.

The set piece is not cleared by Chelsea, but again they get a let-off as the ball deflects into Hannah Hampton's arms.

Pat Nevin
Former Chelsea and Scotland winger on BBC Radio 5 Live

If Barcelona can get an early goal and relax into the game, that is exactly what Chelsea do not want.

They just need to hold Barcelona off for the opening few minutes.

Image source, Getty Images

Chelsea's formation is interesting. It's a back five, but with Niamh Charles unusually as one of the central defenders with Ashley Lawrence at left back.

A bold move by Emma Hayes, we shall see how it pans out.

Emma Sanders
BBC Sport at Estadi Olímpic Lluís Companys

Incredible atmosphere here in Barcelona. Home fans sang the club's anthem before kick-off as the players walked out, ending in a resounding "Barca, Barca, BARCA" cheer. They booed the Uefa anthem heavily and are now signing their version of "Allez, allez, allez" after that chance for Caroline Graham Hansen.

Image source, Reuters

Chelsea are after a return to Spain by winning this two-legged semi. The final is in Bilbao on 25 May.

They have settled down after that shaky start, and are seeing a bit of the ball.

Pat Nevin
Former Chelsea and Scotland winger on BBC Radio 5 Live

Barcelona are fabulous to watch, have brilliant players all throughout the team.

Their attack is special, in the wide areas especially. Caroline Graham Hansen has had an exceptional season. We all know what she is about and what she can do, but doesn't make it any easier to stop her.

This is very nervy from Chelsea, as Ashley Lawrence totally loses Caroline Graham Hansen in the area.

Fortunately for her, Graham Hansen's touch is heavy and Hannah Hampton snaffles the loose ball.

Image source, Getty Images

Immediately, Aitana Bonmati shows what she is about, cutting back on the right and sending in a dangerous low cross.

It is scrambled away rather nervously by Chelsea.

Barcelona have not lost a competitive home match in five years. Could Chelsea be the ones to break that streak?

We are under way.

Image source, Getty Images

Barcelona XI: Coll, Batlle, Paredes, Engen, Rolfo, Bonmati, Walsh, Patri, Graham Hansen, Paralluelo, Caldentey.

Chelsea XI: Hampton, Lawrence, Carter, Buchanan, Charles, Rytting Kaneryd, Cuthbert, Nusken, Leupolz, Ramirez, James.