With the negotiations between the two clubs taking longer than initially expected, Chelsea have finally got their man.
The Senegal international becomes Frank Lampard's seventh signing of the window following the arrivals of Hakim Ziyech, Timo Werner, Ben Chilwell, Thiago Silva, Malang Sarr and Kai Havertz.
Edouard Mendy, who helped Stade Rennais qualify for the Champions League for the first time in their history last season after finishing third in Ligue 1, is expected to be made Chelsea new No.1 replacing the error-prone Kepa Arrizabalaga.
Similarly unproven, Cech went on to become arguably Chelsea's best ever goalkeeper- winning four Premier League titles, four FA Cups, three League Cups, the UEFA Champions League and UEFA Europa League in his eleven year spell.
"As soon as Petr Cech and our technical team identified Edouard as the most suitable goalkeeper to complement our existing group, there was only one player we wanted to bring in.
"Edouard arrives following a season of real success with Rennes, he is ambitious for more, and we welcome him to our club."
However, the Czech was still in-between the sticks for Arsenal when Mendy became a player of interest in December 2018.
It was Cech's former goalkeeping coach (and now scout and head of Chelsea's goalkeeping department) Christophe Lollichon who first identified Mendy as a potential signing when he was still applying his trade at Reims - who were promoted to France's top division a year prior.
So why did Chelsea decide to go with Mendy, over the likes of Jan Oblak, Gianluigi Donnarumma, Dean Henderson, Nick Pope and Andre Onana, who have all been linked with a move to South West London this window?
First, the price
After paying a record breaking fee of £71.6m for Kepa, paying such a sizeable sum for the second time in just two years was not regarded as a suitable option.
As expected, early reports regarding the signing of aforementioned keepers, such as Atletico Madrid stopper Oblak, caused much excitement within the Chelsea fan base.
But it quickly became apparent that the prospect of spending a big on a new keeper was unfeasible- especially after spending over £230m on new signings already in the window.
So when the opportunity arose to sign Mendy for little over £22m (plus add-ons), along with the advocacy of Cech and Lollichon, it became an easy decision to make.
Questions have been raised however on whether Mendy will be able to make the step up and handle life in the Premier League? Or will it be a similar story to Kepa's demise? Was he brought in as a last resort as they couldn't afford anyone better?
Hopefully his numbers will provide some answers.
Mendy is a very solid shot-stopper.
He conceded 0.8 goals per90 last season, which ranked him second best in Ligue 1 behind Predrag Rajkovic and Kaylor Navas.
He kept 9 clean sheets in 24 games compared to Kepa's 8 in 33, with 4 of the 19 goals the Senegalese keeper conceded coming from corners.
Mendy's 6ft 6in frame makes him a significant five inches taller than Kepa.
Despite not being strong physically, Mendy has a clear advantage when it comes to claiming crosses and dominating the penalty area in high positions.
Set-pieces & crosses
This will comes as relief for Chelsea supporters, as for the second successive season, both with Kepa in-goal, the Blues had the worst record in the Premier League for conceding goals from set-pieces.
And when it comes to crosses, Mendy is ranks higher; Kepa - who conceded eight goals from corners in 19/20 - stopped just 7.2% of crosses in the season as opposed to Mendy's healthy 10.2%..
A tendency to stay on his line has been regularly exploited by opponents in the box and caused the backline to lose all trust in the Spaniard's ability.
In short, Mendy commands his area while Kepa orchestrates without conviction.
Post-shot xG & save percentage
Hardly a tricky feat, Mendy's post-shot xG of + 1.7 was superior to that of Kepa's -9.6, given teams managed to find the back against him from almost every angle.
For any keeper in a title chasing side, keeping a good save percentage for the duration of a campaign is paramount.
In terms of Kepa, his save to shot ratio was infamously bad last term- saving only 54.5% of the shots he faced placing him bottom in the Premier League rankings
Mendy however was the third best performer in Ligue 1 for shots saved last season with 78.4%.
Some may argue the Premier League has higher a quality of shots thus devaluing Mendy's percentage, but it'll be some achievement if he manages to do worst than Kepa.
In fact, Kepa did face a higher quality of shots last season (0.35 SQ) by some distance in comparison to Mendy's 0.22 SQ, which supports the idea that Premier League keepers face shots of higher difficulty.
Though this does point to the fact that Mendy had better defenders in front of him, thus the gulf in numbers between the pair.
But with the acquisitions of Silva and Chilwell, this should help solidify Chelsea's notorious 'leaky' defence and clear up any frailties at the back.
Furthermore, it should also result in the SQ of the opposition to decrease and subsequently increase the PSxG, as opposing forwards will have to work harder to create goal scoring opportunities.
Kepa’s attempted pass to Jorginho against Liverpool that was cut out by Saido Mane highlights the deficiencies he has with the ball at his feet.
This is another key factor why Mendy was signed.
Last season, Kepa's completed only 28% of his throws and passes (excluding goal kicks) to Mendy's 47%.
The improvement in distrubtion when it comes to kicking the ball long will provide the side with more pace in attack, with Havertz and Werner latching onto quick clearances from the area- just as Alisson and Ederson do for Liverpool and Manchester City
Even if it doesn’t work as part of an attacking ploy, it will certainly relieve any pressure from teams that press them high up the pitch- like Klopp's men did with great effect last Sunday.
Cech was rightly credited for playing a big part in bringing Mendy to Stamford Bridge.
But the ex-Renne keepers have more in common then first thought.
Here's what their first two Ligue 1 seasons look like in Red and Black:
|Petr Cech||Overview||Edouard Mendy|
|12th||Average league position||6th|
|Petr Cech||Per 90 metrics||Edouard Mendy|
Too big of a step up?
The most important question is how Mendy is going to cope mentally.
Chelsea is a huge step up from Reims and Rennes and it'll be interesting how he'll cope settling into a new dressing.
Is he ready to play at a club where every defeat is a disaster?
Will he be able to cope with potential criticism from an error leading to a goal that Kepa has in the past?
Numbers can't predict that, we can only wait and see.
To conclude, Mendy is a smart choice.
Mendy is substantially better than what Chelsea have right now. If he can cope with the demands with the Premier League, Chelsea have a really solid pair of hands, on their hands.
And with only £20m spent, it was a no-brainer and totally justified.