When Paris Saint-Germain line up against Manchester City at the Parc des Princes on Wednesday for the first leg of their highly anticipated Champions League semi-final, the state of the home side's defence is unlikely to be at the forefront of many minds.

Neymar and Kylian Mbappe, each sublime against defending champions Bayern Munich in the previous round, are the obvious attractions.

The opportunity to see the two PSG superstars go toe-to-toe with an exciting City side, led by Kevin De Bruyne and Phil Foden, is an enticing one.

However, as well as the attacking talent that has allowed City to score 21 times in the competition this season – matching PSG and trailing only Bayern (27) – Pep Guardiola's men also have the meanest defence.

Fellow semi-finalists Chelsea are the sole other side to have conceded as few as three goals in the competition in 2020-21, with that rate of 0.3 conceded per game by far City's lowest across a Champions League season. They have never previously dipped below the 1.0 mark.

The same does not apply to PSG, who have shipped 1.1 per game – a huge increase on the 0.6 per game that carried them to last season's final.

Mauricio Pochettino may have to rely on some big individual performances over the two legs to make up that deficit to a now solid City outfit, whose defensive strength stands at odds with the open approach that cost Bayern.

An open encounter ended in PSG's favour

Chelsea's Champions League playbook

In any season, City's defensive record would be outstanding. The stingiest back line among the past 10 Champions League winners – Real Madrid's in 2015-16 – conceded more often at 0.5 goals per game.

Meanwhile, if PSG were to go on and claim the title while letting in goals at the rate they are now, Pochettino's men would sit towards the bottom of that list. Curiously, the 2016-17 (1.4) and 2017-18 (1.2) Madrid teams were the only European champions since 2010-11 with leakier defences than the Ligue 1 giants this term.

The 2017 victors were also the one side to average fewer clean sheets than PSG, who have kept the opposition at bay in just 20 per cent (two of 10) of their matches in 2020-21. Madrid that season had only a single shutout across 13 games (7.7 per cent).

Yet PSG might still prefer to be counted in that company rather than ranking alongside Chelsea's class of 2011-12.

An inexplicable run to their first Champions League crown saw the Blues face 18.5 shots and 5.7 shots on target per game. Barcelona had won the previous competition while allowing just 6.3 shots and 1.8 on target.

Bayern produced 43 chances worth 3.6 expected goals (xG) against Chelsea in the 2012 final but scored only once and lost on penalties.

It was a defensive triumph that felt unrepeatable, so it is concerning that PSG are facing a comparable 15.7 shots and 5.8 on target per game in this season's tournament.

Chelsea somehow saw off Bayern in 2012

Winning keeper Keylor the key man

Chelsea goalkeeper Petr Cech led the Champions League with 7.8 non-penalty goals prevented in 2011-12, using expected goals on target (xGOT) data. That PSG have made it to this stage despite their defensive deficiencies owes much to the brilliance of their own number one.

Keylor Navas was a regular for each of the three Madrid victories mentioned above, playing a particularly key role in 2015-16. He conceded only two non-penalty goals across 11 games despite facing shots worth 5.3 xGOT, preventing 3.3 goals.

An astonishing 89.7 save percentage that year is the highest mark of any keeper to play 10 or more games in a single Champions League season since at least 2003-04 – Chelsea's Edouard Mendy has 92.6 per cent over nine matches this term – but it was an outlier in Navas' Madrid career.

Only since joining PSG in 2019 has Navas truly underlined his status as one of Europe's elite keepers.

The Costa Rica international prevented 2.6 goals last season, ranking seventh in the Champions League, and 4.9 this term, good enough for second behind only Manuel Neuer (5.2).

In 2020-21, Navas has faced the most shots (157) and made the most saves (47), including a vital penalty stop from Lionel Messi in the last 16. Only Ralf Fahrmann, Rui Silva and Oliver Baumann (four each) across Europe's top five leagues have kept out more spot-kicks than the PSG man (three) in all competitions this season.

After heroically preventing 2.2 goals in the first leg against Bayern alone, Navas was substituted with a shoulder injury at half-time in PSG's next league match.

He still faced Bayern once more three days later but only returned to the team again on Saturday. PSG's hopes rely heavily on Pochettino being able to call on his keeper, who agreed a well-earned contract extension on Monday.

Keylor Navas has been outstanding this season

MVP Marquinhos missing once more?

Having another vital defensive cog back fit again would go a long way to protecting Navas from De Bruyne, Foden and Co.

Captain Marquinhos has been limited to 32 appearances in all competitions this season but has won 78.1 per cent of those games, the best win rate of any PSG player to feature 10 times or more. When he has been absent, PSG have triumphed in just 52.9 per cent of matches, conceding 1.1 goals per game – up from 0.6.

The 26-year-old centre-back was regularly used in the middle of midfield rather than defence last season and, despite the departure of previous skipper Thiago Silva, continued in the role on occasion at the start of this campaign.

When that meant Marquinhos playing in the centre of the pitch while midfield signing Danilo Pereira lined up in defence, the Portugal international complained: "Being a defender is not my job."

It is certainly Marquinhos' job, though, and one he has resumed to great effect since Pochettino replaced Thomas Tuchel.

Among defenders to have played three games or more in the Champions League knockout stages this season – Marquinhos has featured three times – the Brazilian leads the way for clearances (7.7) and blocks (2.6) per 90 minutes and trails only City's John Stones (84.6) in winning 81.8 per cent of his duels.

In Munich, Marquinhos – who also ranks ninth for passing accuracy (90.8) – became the first PSG player to contribute four blocks in a Champions League game since compatriot Silva against Napoli in November 2018. And he scored one of his side's three goals.

Like Navas, though, Marquinhos has since suffered again with injury, a groin issue meaning that 3-2 win was his last appearance, with no risks taken in the return fixture.

"He is training well," Pochettino said after Saturday's win against Metz. "We will see how he is on Wednesday; we hope he will be available."

Life could otherwise be tough for the coach and his oft-exposed keeper against City, when lifting the defensive standard will be as important as the exploits of Neymar or Mbappe.