Even if Jose's reasoning weren't sound, even if he just did it to mess with (or set right) Courtois's head, the pair of world class saves -- the second of which could easily be our save of the season so far -- and a most crucial clean sheet easily validates Petr Cech's surprise selection.
"Courtois played consecutive matches, against Liverpool, Manchester City and Aston Villa, games where he needed to be very focused. Every detail is so important, even when he doesn't touch the ball, the focus must be permanent and I think a goalkeeper can also be tired. The tiredness isn't just physical, it's also from your nervous system."
"Petr has been working really well and hard. In every training session I was getting the feeling his condition was magnificent. Tonight he was the best option for the team, also in terms of leadership. John Terry was ill this morning and he was probably out of the game until the last minute, so I thought I needed Petr's personality and capacity to communicate at the back. The decision was good."
-Jose Mourinho; source: Chelsea FC
Anytime your decision turns out to be a match-winning one, it's probably fair to describe it as "good," indeed.
Jose seems to be putting Courtois's recent bobbles down to mental fatigue, which is probably not too much of a stretch considering that he didn't have any problems with that part of his game earlier in the season. Of course this could all be a diplomatic way of sending a wake-up call to the young man, and his reaction will be crucial ahead of the big games coming up in the Champions League, the League Cup final, and of course our continuing quest for the Premier League trophy.
Either way, there will be a world class pair of gloves safeguarding our net.