The Swindon Town match was billed as an opportunity for Juan Mata to prove that he could put any doubts about his defensive workrate to bed*. Since the only opinions on how he fared that matter are the coaches, let's see how they thought he did.
*An aside -- does anyone else find it funny that Mata was supposed to have trouble fitting into a Jose-Mourinho-style counterattacking team but that the actual issue is that Mourinho wants to play an aggressive high-pressure game that requires the forwards to defend more? Anyone?
If you look at [Mata's] performance tonight, he made Fernando's chance early in the game, he was involved in the goal, so if you take those moments, it's goal-making and goalscoring actions, and then in injury time he conceded the final corner of the game supporting Ryan Bertrand in the left-back spot, which is how he as all night. That's been the message from Jose from day one to all our attacking players, not just Juan Mata.
Jose has made it quite clear what he wants the attacking players to do in all those positions. That message is not just to Juan, it's to Willian, Kevin, Andre Schurrle, all those players. Tonight we are very pleased with Juan's contribution, with and without the ball.
-Steve Holland. Source: ChelseaFC.com
So that all sounds pretty promising. Steve's obviously not the manager, but it sure sounded like he was speaking for him with that bit I bolded. The suspicion at the moment is that, with a bit more defensive work, the Hazard-Oscar-Mata trifecta once again becomes first choice for Chelsea's standard games, and I'd guess we're not really that far away from it happening.