Sergio's side make the trip to Madrid for Sunday's early kick-off with the champions eager to kickstart their campaign after a somewhat unremarkable start to their title defence.
Atletico have won two of their last three La Liga outings but defeat to Valencia prior to the international break leaves them fifth in the table - five points off leaders Barcelona.
In the absence of any top-flight action in recent weeks, discussion has continued in the Spanish media over Atletico's style of play, with critics in some quarters questioning the physicality and aggression of Diego Simeone's men.
However, Simeone is seemingly more concerned with upping his side's intensity in training, having reportedly hit out at their efforts during a practice match on Friday.
As the league holders prepare to return to action, full-back Ansaldi stated he was not interested in criticism from outside the club.
"We know it's going to be like another final for us. What we want is to get ourselves back within the winning atmosphere this team has always had," he explained.
"All that matters to us, is getting out there and playing our football.
"We'll keep playing our own game, which is what brings us our rewards and which last season brought so many important achievements. If the way we play upsets others, then they'll just have to stay upset as far as I’m concerned.
Fixtures between Atletico and Espanyol are traditionally tight affairs, with the last four meetings won by a 1-0 scoreline - something visiting goalkeeper Kiko Casilla thinks is likely to be the case again this weekend.
A haul of nine points from their opening seven fixtures sees Espanyol sit eighth and Casilla is confident of adding to that, provided they can cope with Atletico's physical presence.
"They are a very difficult team at set-pieces. Set-pieces are a basic part of their strategy and they also have players like Koke and Raul Garcia who can hit the ball well," he explained.
"Defensively, Atletico are one of the best teams in La Liga. If we have a shot on goal, I don't think there will be many, we must be efficient.
"For our part, we need to be very focused at the back. We're going to try and make things difficult for them and get a positive result for us."
Simeone's squad appear to have returned from international duty unscathed, having taken part in training on Friday, though they will be without the suspended Alessio Cerci, with Hector Moreno (tibia) Espanyol's only absentee.
‘The pure simplicity of the way Slot has managed the squad is probably the biggest thing I could say about him. It’s not broken, so let’s get on with it’: Liverpool legend full of admiration for Jurgen Klopp's successor at Anfield
‘I trained at Spurs and thought they’d give me a chance. But I received a letter thanking me but saying they didn’t think I was good enough – I was gutted’: How Tottenham missed out on signing Wales legend John Toshack
