The two teams meet at Cornella-El Prat on Sunday with the Primera Division champions looking for victory against Mauricio Pochettino's men in the first Barcelona derby of the campaign.
Guardiola is expecting a tricky test from Espanyol and spoke of the similarities between the two sides.
"We try to take every game seriously but this is the derby - a fixture where there has been many games which makes us know what to expect and what we are going to find," the 40-year-old told reporters in his press conference.
"If we are not in good shape, we will be in trouble. Espanyol play well and are a team with a similar philosophy to us, even if we do have the greater purchasing power. It is certainly a special event during the year."
Barcelona should be boosted by the return of Andres Iniesta who tore a muscle in the 9-0 thrashing of Hospitalet in the Copa del Rey before Christmas.
"He [Andres Iniesta] will have a medical but he almost certainly will [be available]. We will decide on the team later on. I will see how they all are and decide on that but it looks like it could be good news," he added.
Guardiola was also quizzed on any potential January signings and ruled out any strikers joining the club even though David Villa is expected to miss the rest of the season with a broken leg.
"We are not looking to sign anyone this month, we're happy with the players we have," he said.
Guardiola concluded with a few words on the news that the International Federation of Football History and Statistics (IFFHS) named him the coach of the year for 2011.
"These awards are given because the team have won, not because I'm necessarily the best. I do not consider myself better than my colleagues. I'm at a club with a philosophy, purchasing power and good players coming through the system so we must not give too much importance to this award," he added.
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