Petr Cech has used social media site Twitter to take a dig at Manchester United.
The veteran goalkeeper responded by saying that Courtois was performing ‘much better than the team you support’ after United’s poor start to the season.
England’s most successful club were expected to make a charge back into the top four this season, under Louis Van Gaal, but their early season form has been awful.
After losing to Swansea City on opening day they struggled to a draw with Sunderland in their most recent fixture and already concerns have been raised that there could be a repeat of last season on the cards at Old Trafford.
United had previously finished down in seventh position, but Van Gaal’s arrival brought a new found impetus to the club.
However, that has already evaporated with the squad looking far short of the quality required to challenge any of the Champions League chasing clubs.
It has led to United going off in search of quality, with Angel Di Maria set to be announced, but even with more additions there is no guarantee that they will make a recovery from last season’s dismal campaign.
Cech, meanwhile, is also facing an uncertain future. He has lost his place to the aforementioned Courtois in between the Chelsea sticks and has been linked with a move away from the club already.
The 32-year-old has been Chelsea’s regular stopper for the most part of the past decade, but his young Belgian counterpart has usurped him this season.
Jose Mourinho is understood to still want to keep Cech, but a goalkeeper of his quality is wasted on the substitutes’ bench and, with some of Europe’s biggest sides linked, keeping him may be a struggle.