Petr Cech was Arsenal's one and only summer signing last year, but he has proved a superb addition to a team in desperate need of a top class goalkeeper.
Chelsea let him leave in the belief they had two, and as Cech was the oldest, he had to go.
Thibaut Courtois was Chelsea's man, and he had earned it, winning a Premier League winner's medal in 2014/15, with Cech sitting on the bench.
Last night the Belgian stopper was in goal as Chelsea slipped to a 2-1 loss to Paris Saint-Germain, and could have done better for Edinson Cavani's winner, beaten in a one on one by the Uruguayan.
It was the sort of goal Chelsea fans have been accustomed to Petr Cech saving over the past decade, offering a presence which Arsenal are currently benefiting from.
Arsenal are competing for the league title, while Chelsea are in 12th position after a nightmare season, and were dealt a setback in their Champions League hopes last night.
The way Courtois conceded the winner had some Chelsea supporters ruing the lack of Petr Cech, and their comments won't fail to make Arsenal fans smile.
Here is a look at the reaction and subsequent comparisons...
See how foolish Courtois just allowed that get passed him, Cech would have saved it— #Lafiaji (@itz_Jefe) February 16, 2016
Courtois is so overrated. He's nowhere near the level of Cech— Sam (@SuperCFC) February 16, 2016
Honestly feel Courtois could've done better for the second goal.— Marc™ (@Tzar_Marc) February 16, 2016
Still don't believe he's better than Cech or ever will be.
We should have never let peter cech go, my confidence in courtois is starting to fade— prince boateng (@gashaw_hailu) February 16, 2016
Seeing that Cavani goal made me realise that Courtois can never emulate even half a part of Cech #PSGCHE— Adnan Siddiqui (@asiddiquiii) February 16, 2016
Cech is SO much better than Courtois why did we sell him ffs— Dan Williams (@DannyyBoy94) February 16, 2016