Holders Barcelona put themselves in the driving seat with a resounding 4-1 over Chelsea in the first leg of their Women's Champions League semifinal on Sunday, with substitute Clàudia Pina netting twice.

Alexia Putellas missed an early penalty for the hosts before Barca's Polish striker Ewa Pajor broke the deadlock in the 35th minute, ghosting in behind the defence to latch onto a through ball from Putellas and slotting it in at the far post for her 36th goal in 39 games this season.

Coming up against the Catalans at the semifinal stage for the third season in a row, Chelsea were left floundering in their wake for much of the game at the Estadi Johan Cruyff.

They went two down in the 70th minute when Pina netted her first goal four minutes after coming off the bench for Caroline Graham Hansen.

"It's a good result. It's was a complete performance and we have a three goal lead," Pina said after the game. "It's a small advantage, but it's not over.

"Everyone wants to play every game. I was keen to get on. I have a really good understanding with Alexia. She was already telling me where the spaces are. I just had to give her the ball and I knew she would give it back. I am really happy to help the team whenever I can.

"Barça always go out to win, to try and play in our way. That's what we will do and try and win the game."

Sandy Baltimore, who slipped in the build-up to Barca's second goal, redeemed herself four minutes later by reducing the deficit, picking up a pass from Catarina Macario and flashing a shot in at the far post.

The Londoners rushed to retrieve the ball to restart the game, but instead it was the home side who scored next, Irene Paredes steaming in at the far post and sending an unstoppable bullet header into the net to restore Barca's two-goal advantage from a corner in the 82nd minute.

That goal took the wind out of Chelsea's sails but Pina was not finished.

She added a fourth goal on the stroke of full time to give her side, who are seeking to win the title for a third successive year, a commanding lead ahead of the second leg in London next Sunday.

In Saturday's other semifinal, Lyon beat Arsenal 2-1 in London in their first leg, with the return also taking place next Sunday.