Chelsea v Paris Saint-Germain - UEFA Champions League Quarter Final Second Leg

Ever since Chelsea were pitted against Atlético Madrid in the Champions League semi-final draw, coverage of both clubs has tended to focus on one man. Little wonder. The story of Thibaut Courtois, owned by Chelsea but enjoying a phenomenal season on loan at Atlético, would have been compelling enough even without the contractual clause which threatened to stop him from taking part.

The terms of the player’s loan agreement state that his parent club must be financially compensated – reportedly to the tune of £2.5m – every time that he appears against them in a competitive match. Atlético’s president, Enrique Cerezo, initially suggested that Courtois simply would not be able to play, saying: “it’s a number we cannot afford”.

But then Uefa intervened, ruling that the clause was unenforceable. The governing body “strictly forbids any club to exert, or attempt to exert, any influence whatsoever over the players that another club may (or may not) field in a match”.

Either way, it is telling that Chelsea would place such a high value on Courtois’s presence in the first place. They rate the 21-year-old very highly indeed. Increasingly, so does the rest of the world.

Courtois has been with Atlético now for three seasons, and his performances only continue to improve. He has kept 19 clean sheets in 32 La Liga games this season, plus a further four in the Champions League. His efforts in the latter competition have often been eye-catching, from the stunning reflex stop he made to deny Milan’s Andrea Poli in the last-16 to his second-leg shut-out of Lionel Messi et al during Atlético’s quarter-final win over Barcelona.

There are those who would already name Courtois as the best goalkeeper in the world. The former Atlético striker Radamel Falcao did so last November, while Jimmy Floyd Hasselbaink – who played for both the Spanish club and Chelsea during his career – recently claimed that only Bayern Munich’s Manuel Neuer could compare.

The Dutchman was prepared to rank Courtois above the man who will start in goal for Chelsea on Tuesday night. Petr Cech was once considered to be the best in the world himself, but lately seems to have slipped out of the conversation. He knows very well that he is likely to face a battle to keep his job when Courtois’s loan deal expires in the summer.

Impatience for change is building, as it tends to do where young talent is involved. Cech’s qualities were called into question after he made costly mistakes on two of Paris Saint-Germain’s three goals during the first-leg of Chelsea’s own Champions League quarter-final last month. The next day’s edition of the Daily Star newspaper carried the unequivocal headline: “TIME FOR KEEPER TO CECH OUT!”

It was a preposterous demand – and one that came to look even more so after Cech’s clean sheet had helped Chelsea to overturn the result in the second leg. The goalkeeper has made mistakes this season, not least those in Paris, but for the most part he has enjoyed a very solid campaign. In fact, from a statistical standpoint, he’s been outstanding.

Cech has kept 16 clean Premier League sheets so far in 2013-14, three more than any goalkeeper in the division, and is conceding at a rate of just 0.71 goals per game. Nor is this simply a case of him benefitting from the quality of Chelsea’s defence. According to NBC’s stats, Cech’s save percentage for the season stands at 76.7%. Only Vito Mannone, on 77.9%, has done better.

Such achievements are hardly a flash in the pan. Cech had the Premier League’s best save percentage last season, too, when he also made more stops than any other goalkeeper among England’s top four teams. He has kept a club record 219 clean sheets so far in his 10 years at Chelsea, and has shown little sign of slowing down.

But Cech knows better than most that he cannot afford to rest on his laurels. After all, he was a young upstart himself once, arriving at Chelsea as a fresh-faced 22-year-old in the summer of 2004 – after a short loan spell at Rennes – and immediately snatching the starting goalkeeper’s job away from Carlo Cudicini.

During an interview with Sport magazine last summer, Cech recalled the mood of supporters at his Premier League debut – a home game against Manchester United. “I remember coming out for the warm-up, and you see there is a huge reception for Carlo,” said Cech. “Everyone is singing his name, and then the line-ups come out and I think the supporters were like: ‘Who is that guy?’ I knew I had to really deliver if I really wanted to keep my place.”

That he did, playing his part in a 1-0 victory over United and never relinquishing his spot thereafter. Cudicini, previously considered to be one of the better goalkeepers in the Premier League, would not be a full-time starter again until he joined LA Galaxy in Major League Soccer almost a decade later.

Cech has no intention of imitating the Italian’s career path. At 31 years old, he knows that he still has plenty of good years left in him, and does not want to waste them sitting on a bench. Indeed, one of players he looked up to most of all during those early years in English football was Nigel Martyn, a man that Cech admired precisely because of the way he kept performing to a high level even as he closed in on his 40th birthday.

Long before Martyn, though, Cech’s first true goalkeeping idol was Edwin van der Sar. “I remember when Ajax started playing with [him] basically as a libero,” said Cech during his interview with Sport. “Everyone was like: ‘Wow, they are playing like this with their goalkeeper!’

“But then you realise that this was the way forward – a goalkeeper shouldn’t just be in the goal to catch the ball when it comes to him. He is an extra player, he can see things from the back, he can pass the ball. Players don’t just kick the ball for the sake of it, so why should a goalkeeper? You always want to find the solution that enables you to retain the ball, and you always need to know how to control the space behind the defenders.”

It is a style that Cech has sought to emulate in his career, advancing high up the pitch when his teams are in possession. It is also one area in which he might claim an edge over Courtois. In a piece for the Guardian earlier this month, Sid Lowe noted that Barcelona, linked with a bid for the Belgian, had distanced themselves from such a move by raising concerns about his ability to distribute the ball with his feet.

Then again, there is always a fair bit of gamesmanship where potential transfers are concerned. And a Barcelona approach for Courtois would surely be rejected in any case. If Chelsea were to even consider allowing the player to leave, it would likely only be in a deal with Atlético, and presumably one that saw Diego Costa move in the opposite direction. Even that might not be sufficient.

Chelsea, though, are going to have to face up to some difficult decisions this summer. Courtois has already expressed impatience at his situation, suggesting that he would like to know where his long-term future lies. With just two years left on his contract at Chelsea, he might soon be in a position to start making ultimatums.

But Cech has an opportunity over the next fortnight to prove just how much he has left to offer. A clear-eyed look at his performances this season suggests that it might be more than he often gets credit for.