Barcelona are yet to taste defeat this season, and Chelsea have the unenviable task of trying to change that fact as they prepare to take on the Catalans in the first leg of their Women's Champions League semi-final clash on Saturday.

The pair have become well-acquainted in recent times, meeting in the 2021 final and at this same stage of last season's competition, with Barca unbeaten against the Blues in those three meetings. The reigning European champions are favourites ahead of their fourth and fifth encounters, too, having won 35 of their 37 outings in all competitions this term.

But Chelsea are the champions of England, they are a seasoned Champions League team and they have a squad full of winners. With manager Emma Hayes set to depart at the end of the campaign to become the new head coach of the United States women's national team, the Blues have an extra layer of motivation as they aim to deliver the one trophy she has yet to lift in her time with the club, too.

The question is, can they utilise those strengths to overcome an opponent that looks simply unbeatable right now? GOAL highlights six things that will be key if they are to secure a shock win...

Use Stamford Bridge

It sounds simple, and it is easier said than done, but it is imperative for Chelsea to get a good result in the first leg and stay in the tie if they want to progress to the Champions League final. Last season, the Blues became the first side to stop Jonatan Giraldez's charges from winning at Camp Nou, holding them to an admirable 1-1 draw, but not one that helped them win the tie as Barca had already emerged 1-0 victors at Stamford Bridge.

That the home and away legs are reversed this time around could give Chelsea a slight advantage. After all, the Blues showed in their run to the UWCL final back in 2021 just how good they can be in those second legs, with Hayes and her staff excellent in assessing the first game to make tweaks for the second. That was particularly evident in the semi-final victory over Bayern Munich, in which the Blues had to come from 2-1 down. It was a factor last year, too, as Chelsea were better in their second leg against Barcelona, but winning at Camp Nou always felt too big of an ask.

The second leg will be at Stamford Bridge this year and that is better for Hayes' side, but only if the tie is still alive. They cannot give themselves too much to do in London.

Find the right balance

So, what do Chelsea need to do to get a result in Barcelona? Well, first things first, Hayes needs to get the balance of her team right. There's no two ways about it, Chelsea will be starved of possession in the semi-final and opportunities to cause Barca problems will be rare and likely on the counter. The Blues need some forwards who can be a threat in transition then, but they also need to be well stocked defensively.

It's in midfield where this is probably most significant. It's common to see a playmaking presence there, with Lauren James, Fran Kirby or Jelena Cankovic operating in front of Erin Cuthbert and one of Sophie Ingle or Melanie Leupolz.

However, that is probably a luxury Hayes needs to sacrifice for the trip to Catalunya as the midfield three tries to stifle Patri Guijarro, Aitana Bonmati, Alexia Putellas, Keira Walsh or whichever talented technicians start in the centre for Barcelona. The question is how the Chelsea boss ensures that doesn't leave her forwards too isolated or lacking in support when they are on the attack.

Figure out James’ role

Part of that balance is understanding how to use James. Last year, Hayes had her come off the bench in the two games against Barcelona, clearly hoping her team could stay in the game and that the England star could provide a spark when they pushed further forward later on, especially with the Catalans at their most tired at that point. Yet, the 22-year-old struggled to really make an impact in either leg. Generally speaking, she is probably not at her best when used as a super-sub, for club or country.

With James still developing the defensive side of her game as a winger and it unlikely she plays as a No.10 given the aforementioned reasons, perhaps the best role for her is as a false nine, one she has shone in several times this season, with someone like Mayra Ramirez then able to make an impact from the bench.

Finding that optimal formula is Hayes' task, anyway, and it all depends on whether or not James is able to play, with there some uncertainty over her fitness ahead of the first leg.

Test the centre of defence

Also a factor in how Hayes decides to use James is that if there is one area of the Barca team to target, it is probably the heart of defence and, more specifically, its lack of pace. The Catalans are currently without Mapi Leon, arguably the best centre-back on the planet. Of course, with their squad depth they do still have some excellent options, but that area has lost a bit of speed in Leon's absence.

That would make James an attractive choice to start in the No.9 role, though Ramirez has some real speed as well, especially once she gets going on one of her destructive runs forward.

Chelsea will have a tough task in getting the ball to whoever is leading the line, especially with the Barca defence protected by one of the game's best holding midfielders in Patri, but if they can figure out a way to put the Catalans on the back foot and run at them in central areas, it could give them some joy.

Keep Graham Hansen quiet

Barca have plenty of threats of their own, though, and one that Chelsea will absolutely need to keep as quiet as possible is Caroline Graham Hansen. The Norwegian has been her team's star player this season and the Blues know all about how decisive she can be in these big games, as her two goals allowed Barca to emerge victorious in their semi-final tie last season.

It's likely that Chelsea will act to cover the left as much as possible to counter Graham Hansen's threat. How exactly? Eve Perisset is an excellent one-v-one full-back, but always operates on the right. Would Hayes switch her to the other side on this occasion? Could Niamh Charles, the attacker-turned-defender who is often deployed on the left, be replaced by a more natural defender? Or will Hayes simply play a winger in front of Charles who almost acts as a second full-back, to provide protection?

That said, it's important that Chelsea don't focus too much on Graham Hansen, either. They need to try and reduce the influence she has on the game, for sure, but if they become overly fixated on her, then another of Barca's world-class attackers will just hurt them instead.

Devise an effective Plan B

Hayes could get everything right in terms of setting her team up, creating a game plan and choosing the best XI for the match, and something could happen out of Chelsea's control to break the deadlock. One of Barca's stars could find the top corner with a wonder-strike from 30 yards, there could be some freak own goal - like the one when these two met in the UWCL final in 2021 - or Barca could simply find a way to counter Chelsea's plan.

Having a clever, alternative method to secure a result is just as important, then. Against Manchester United last weekend, Chelsea did not have that. At 2-1 down, they needed a goal to stay in the FA Cup and Hayes turned to her bench to bring on Catarina Macario, Fran Kirby and Aggie Beever-Jones, among others, but there didn't seem to be a clear plan of how to cause United problems with such an overload of attackers on the pitch. Indeed, the chances actually dried up when they were introduced.

Hayes will have to be a little more savvy for these games against Barca, especially because it's extremely unlikely that they will be pinning the Catalans back in their own box for large spells like in that game, regardless of the scoreline.