With the first matchday of UEFA Women's Champions League knockout action throwing up some unexpected results and magnificent drama, this week's offering promises to bring even more excitement.

Four last-eight ties will conclude across Wednesday and Thursday, with four sides emerging with a place in next month's semi-finals.

Last season's finalists – defending champions Barcelona and runners-up Lyon – head into their second-leg matches with important advantages, as many may have predicted.

But while most supporters would have expected Chelsea and Arsenal to be ahead in their respective ties, both those Women's Super League giants find themselves in real trouble, looking to overturn 2-0 deficits against Manchester City and Real Madrid respectively.

With four of the eight sides involved being former champions, the calibre of teams could not get much better, and with a place in the semis up for grabs, the stakes are high.

Ahead of the quarter-final second-leg clashes, we are here to give you the low-down on each tie, run through the key data and see how the Opta Supercomputer predicts it will all play out.

Lyon vs Bayern Munich 

Continental heavyweights Lyon head into this home clash with a 2-0 advantage over the German champions from the first leg.

They will feel confident of advancing, as they have gone through in 13 of their 15 previous quarter-final appearances (no other club has reached the semis more than eight times).

Lyon have won three of their four UWCL games against Bayern (L1), including their only prior fixture on home soil – a 2-1 victory in November 2021.

After losing their last two UWCL games against Arsenal and Lyon, Bayern will be looking to avoid losing three matches in succession for the first time in the competition.

They will have to overcome all the odds to win this one, as the Opta Supercomputer only gives the German side a 17.6% chance of getting a win on the night, whereas eight-time champions Lyon are favourites with a 62.6% win probability, and it is 19.8% for the draw.

Tabitha Chawinga and Melchie Dumornay were the providers of Lyon's goals in the first leg and Dumornay could prove a problem for Bayern once more in the second leg.

Only Barcelona's Ewa Pajor (17) has managed more shots on target than Dumornay in the competition this season (14), while only four players in the competition have created more chances than her 17.

Arsenal vs Real Madrid

The below-par playing surface, churned up by wet and windy Madrid conditions, dominated the headlines after last week's first leg.

But that will now be of little comfort to Arsenal, who have left themselves with a mountain to climb in the return leg.

Trailing 2-0, the Gunners are looking to progress from a UWCL knockout tie after losing the first leg away for the second time in succession, following their 2022-23 quarter-final turnaround against Bayern, with the Gunners progressing three times from seven such occasions overall.

Madrid, meanwhile, are looking to reach the semi-finals for the first time ever. Las Blancas are also aiming to make it three away victories in a row in the competition, as many victories as they enjoyed in their 11 games on the road before that (L8).

With the tie finely poised, the Gunners will welcome the Spanish side to the Emirates Stadium and the Opta Supercomputer fancies the hosts to win on the night.

There is a 66.9% win probability for Arsenal, with Madrid winning 15% of our pre-match simulations and 18.1% being drawn – either of those latter outcomes would be more than good enough for the visitors.

In the first leg, Arsenal mustered a total of 13 shots (via nine different players) to Madrid's five but still lost by two goals.

Those 13 efforts are the second-most by a team to draw a blank in a knockout-stage game across the last two editions, after Lyon in last season's final against Barcelona (14 shots, no goals).

And after winning a first Clasico against fierce rivals Barcelona, it has been an incredible week for Madrid. If they can cap that with progression in this tie, it would show stunning progress from Alberto Toril's team.

Madrid duo Signe Bruun (five goals, three assists) and Linda Caicedo (four goals, four assists) are the top two players for goal involvements in the competition this season, with the latter racking up five goal contributions in her last four games in the competition.

Barcelona vs Wolfsburg

The reigning champions are firmly in the driving seat after a 4-1 first-leg victory and still look like the team to beat in this competition as they strive to win a third consecutive title, a feat only Lyon have previously managed (five in a row from 2015-16 to 2019-20).

Barca are looking to write more UWCL history by reaching the semis for a seventh consecutive season – even the great Lyon teams only managed six in a row at their best.

However, the Blaugrana are not unbeatable, and their first-ever defeat in El Clasico on Sunday, when they went down 3-1 at home to Madrid, may offer Wolfsburg hope.

Barca lost their first home match against German opposition in the Champions League, going down 2-0 to Wolfsburg in March 2014, but they have since won each of their last five by a combined scoreline of 15-1 – beating four different opponents during this time (Bayern twice, Hoffenheim, Wolfsburg and Eintracht Frankfurt).

Wolfsburg's Sveindis Jonsdottir has the best expected goals (xG) overperformance in the Champions League this term with +2.67, netting four goals from an xG of just 1.33.

Wolfsburg have lost two of their last three away matches in the UWCL (W1), as many defeats as they suffered on the road in their previous 15 in the competition (W9 D3).

Ballon d'Or winner Aitana Bonmati has created 24 chances in the competition this season, the most of any player, while no player has provided more assists this term than her four, with the 27-year-old assisting Barca's third goal in the first leg of this tie.

The Opta Supercomputer is in no doubt about the result of this one, giving Barcelona the highest win probability of any team involved in this week's matches.

They win on the night in 73.1% of our pre-match simulations, while the draw is a 15.6% chance and Wolfsburg only triumph in 11.3%.

While there might be drama across the other ties, our predictive model clearly thinks Barca's progress will be serene.

Chelsea vs Manchester City

With these two sides meeting four times in 12 days across three competitions and twice in the UWCL, an incredible saga concludes at Stamford Bridge with Chelsea hoping to overturn a 2-0 first-leg deficit.

Sunday's WSL clash between the teams saw Chelsea fight back from a goal down to earn a 2-1 win at the Etihad Stadium, with Erin Cuthbert coming off the bench to score a last-gasp winner.

The Blues therefore find themselves 2-1 up in this mini-series of games, having also won the League Cup final against City to open the stint one week earlier.

But when it comes to the state of the Champions League tie specifically, City have impressively put themselves in the driving seat.

This will be only the second time the two sides have met in this competition, after the Citizens' 2-0 win in the first leg last week. The Blues had won each of their four games in the competition against fellow British sides prior to that defeat.

Chelsea have been eliminated from five of their six Champions League knockout-stage ties when losing the first leg, with the exception coming against Bayern in the 2020-21 semi-finals (lost 2-1 in the first leg away, won 4-1 in the second leg at home).

City, on the other hand, have progressed from all nine of their Champions League knockout ties when winning the first leg.

In the competition overall, the last team to be eliminated from a two-legged tie after winning the first leg by multiple goals was BIIK Kazygurt Women, against Barcelona in the 2018-19 round of 32.

The UWCL trophy has proved elusive for Chelsea, and they may feel it is simply not meant to be in this competition after their first-leg defeat.

But they must hold on to the fact they have won five of their last six home games against City across all competitions (L1), though they were beaten 2-0 in the 2018-19 League Cup semi-finals on the last occasion they hosted the Citizens outside of WSL play.

Their Achilles' heel last week was none other than WSL all-time leading goalscorer Vivianne Miedema. She has scored 12 goals across her eight appearances in the Champions League knockout stages since the start of the 2019-20 campaign.

In that period, the Dutchwoman has the best minutes-per-goal rate in the knockout phase of the competition, among players to net more than five times (52 minutes).

With Chelsea still chasing a quadruple and being in strong form overall, they certainly cannot be written off. However, City have proved across the three meetings so far in this run that they can compete with the Blues.

The Opta supercomputer is highly confident Chelsea will win on the night, with their win probability rated at 60.5%. However, they need a win by at least two goals to stand any chance of progression.

City, despite their good form and win in the last leg, have just an 18.8% chance of winning on the night and a 20.7% chance of securing a draw, which would be more than enough to secure a famous triumph in this pivotal tie.