Chelsea's goalkeeping coach Christophe Lollichon has praised Petr Cech's attitude but revealed the Czech finds it "difficult" to be second-choice to Thibaut Courtois.
After being the mainstay of Chelsea's starting XI for more than a decade, Cech, 32, has found himself in the unfamiliar position of backup this term, making just four Premier League starts as Courtois, 22, has established himself in Jose Mourinho's lineup.
Courtois was recently dropped for the Blues' Premier League win over Everton with Mourinho citing the need for the young goalkeeper to resharpen his mental focus, but the Belgium international returned for Tuesday's Champions League encounter with Paris Saint-Germain.
Lollichon, 50, who moved to Stamford Bridge from Rennes at Cech's request when he made the same switch in 2004, admitted to RMC that the Czech international was struggling to come to terms with his new status.
"Since the start of the season, we've known that we have two of the three or four best goalkeepers in the world," he said. "Whether it's one or the other who plays, it doesn't change anything. They are two big goalkeepers both in terms of size and talent.
"Of course it's difficult for Cech, who has been first-choice for 14 years in the clubs he's been at and who has been voted the Premier League's best goalkeeper several times, to be passed by a 22-year-old kid. He's a great pro who doesn't complain to the press, and who prepares himself as if he were going to play the next match."
Courtois justified Mourinho's choice with a superb display in the 1-1 draw in the French capital, making a string of saves to deny the hosts and leave Chelsea well placed to reach the last eight and earn the praise of Zlatan Ibrahimovic.
The Blues' confidence will be bolstered by the knowledge they lost the first leg of their quarterfinal tie with PSG 3-1 last season before progressing on away goals thanks to a 2-0 win in the return at Stamford Bridge.
Despite Chelsea achieving an improved result in the opening 90 minutes of the teams' tussle this term, Lollichon claimed the draw was actually not as damaging as it may first appear for PSG.
"Right now, the scoreline would take us through," he added. "But isn't the result actually perhaps more beneficial to Paris? They have to play rather than try to defend a result. Now, they have to go out to get a result."