Third time lucky for Chelsea against Barca in semi-final?

Chelsea are still on course to win a quadruple for the first time in the club's history.

To achieve that feat, they must also do something else they have never done before, which is to get past Barcelona in the Women's Champions League knockout stage.

Having already won silverware this season in the League Cup, Sonia Bompastor's side have reached the FA Cup final and sit three points clear at the top of the Women's Super League with four games to play.

But to win the European trophy that has so far eluded them, their immediate task is to beat three-time winners and current holders Barcelona over two legs in the semi-finals.

Sunday's first leg takes place in Catalonia at the 6,000-capacity Johan Cruyff Stadium (kick-off 17:00 BST), before the return leg is played at Stamford Bridge on 27 April (14:00 BST).

Chelsea have lost to Barcelona at this stage of the competition in the past two seasons, but what are their chances this time?

Three defeats in 38 games across all competitions is hardly cause for concern, but for Barcelona it is uncharacteristic.

Pere Romeu's side are seven points clear at the top of Spain's Liga F but have been beaten twice in the division this season, losing to strugglers Levante and suffering a first-ever Women's Clasico defeat by Real Madrid.

They also lost their opening Champions League group game at Manchester City.

Barcelona have lost more games, scored fewer goals and conceded more at this stage of the season than in any of their previous three campaigns.

"It's ridiculous to say they are not as dominant because they are seven points clear and in the semi-final of the Champions League," Spanish football journalist Alex Ibaceta told BBC Sport.

"This is probably their weakest season. The style of play has changed, it's not as fluid as it was in the last few seasons, but they are still dominant and still Barcelona.

"This game is a blank sheet. The highs and the lows of the season, mentally they are very able to erase those moments and just focus on Chelsea."

The good news for Chelsea is that, statistically, Aitana Bonmati is having her least effective season in recent years.

The bad news? Alexia Putellas is back to her best.

Two-time Ballon d'Or winner Putellas missed 10 months with an anterior cruciate ligament injury sustained in July 2022 but is playing a starring role again this season.

"It was tentative at times for Putellas when she came back from her ACL," Liga F and Women's Champions League commentator Chris Sharples said. "She was playing in the lower grade games and coming on as the impact player in the bigger games.

"This year she looks like she is that animal again in terms of when she was at the peak of her powers and winning the Ballon d'Or."

Putellas is Barcelona's second-highest scorer this season behind Ewa Pajor, with 18 goals in 31 games in all competitions.

Having a recognised number nine in Pajor, who joined Barcelona in the summer from Wolfsburg, has alleviated the attacking pressure on Bonmati.

"Before it was a false nine role which created space in the box for Aitana to score, and now it is Ewa Pajor taking the reins and staying central," Ibaceta said.

"Alexia definitely has a role in Aitana being deeper and less important in the midfield, but the goals are coming from different directions. Aitana is Aitana at the end of the day, but she is not in the spotlight as much as she was in previous seasons."

We can expect plenty of action down Barcelona's left side and Chelsea's right, which is where both sides create the majority of their chances.

Ibaceta anticipates Chelsea will have plenty of space on that side - setting up the prospect of a fascinating tactical battle as the likes of Lucy Bronze and Johanna Rytting Kaneryd face off with Putellas and Salma Paralluelo.

"Essentially what Barcelona do is put a winger on the left side for decoration," Ibaceta said.

"Esmee Brugts comes into the middle to create a midfield four and that entire left side of the pitch is left for one person.

"It is the biggest strength of Barcelona, they are able to leave an entire wing for the full-back, but that does leave the backline quite vulnerable. Against Chelsea it is not going to be the easiest thing to do.

"Mapi Leon and Irene Paredes are good but they are slow and a bit older now. They are very open to making mistakes, especially with strong players and in a physical battle, they do struggle with that."

Barcelona typically press much higher than Chelsea but have shown in their defeats this season that they are vulnerable to conceding on the counter attack, where Chelsea's forwards, particularly Mayra Ramirez, thrive.

"How many goals have we seen where Mayra is cutting through?" Sharples asked.

"Barcelona play such a high line, which they are used to doing in Spain because nobody is getting at them.

"But if you can get at them with speed and power, down the flanks especially, they can be exploited."

Chelsea will hope that having serial Champions League winner Bompastor on their side can finally help them overcome their nemeses.

The Frenchwoman lifted the trophy as a player and manager with Lyon and is the only coach to have defeated Barcelona over a tie in the competition in the past four years.

"At this stage of the season, this is when the big teams arrive," Sharples said. "Barcelona want to dominate like Lyon have previously.

"They want history themselves. These are the games where you then turn up and show why you want to be history makers. Chelsea have a great chance of beating them, but it's still Barcelona and you just don't know what is going to happen.

"I think whoever wins this semi-final will go all the way and win it."