Champions Barca let slip a two-goal lead to draw 2-2 at Real Sociedad and Real Madrid capitalised with a 4-2 home win over Getafe that was not as comfortable as the scoreline might suggest.
"They talk of a league of only two teams and this shows contempt to the others who are doing better and better and demonstrating their desire to beat us," Barca coach Guardiola told reporters in San Sebastian.
"It's a good lesson for the future. Sociedad's goals arrived when we were playing our best but it shows that in football you always have to be completely alert."
Xavi and Cesc Fabregas put Barca in control, while Lionel Messi, David Villa and Andres Iniesta started on the bench, but they grew sloppy and conceded two goals in quick succession after the break.
There was a heated debate over the growing financial disparity between the big two clubs and the rest of La Liga after the opening round of matches saw Barca and Real win 5-0 and 6-0 respectively.
SMASHED RECORDS
The two richest teams in the world in terms of revenue have smashed records in the last two seasons while they have duelled for the title, finishing more than 20 points ahead of third-placed Valencia each time.
Mourinho, who has had some high-profile clashes with his former colleague at Barcelona, agreed with Guardiola.
Real were made to sweat against Getafe, after two goals from visiting striker Miku unsettled the Bernabeu, and home coach Mourinho said the debate over the last few days had perhaps led to complacency in his squad.
"Maybe the players were drunk on too much information and news about how easy the league would be and in the end it made things complicated," the Portuguese told a news conference. "All these teams that are supposed to be bad I don't agree.
"All of them are professionals, the coaches and the players. For me all the matches are tough.
"Throughout the season you'll get a few 5-0s or 6-0s but there are going to be difficult games. We will definitely drop points," added Mourinho.
