The Italy goalkeeper was furious at seeing Paris Saint-Germain's unbeaten record ended on Saturday afternoon, but maintains that his team-mates will continue to look ahead
The Italy international conceded midway through the second-half after Mamadou Sakho turned into his own net, before Pierre-Emerick Aubameyang sealed the win, with Guillaume Hoarau notching a consolation a minute before full-time.
Zlatan Ibrahimovic was also sent off for a high tackle on goalkeeper Stephane Ruffier, to round off a miserable afternoon, but Sirigu opted to blast the press after the game for revelling in PSG's disappointment.
"[The media] exaggerates by saying certain things," he told RMC Sport.
"A defeat is not the end of the world. Sometimes we play well, other times we play badly. That's it. There is no clear explanation, there is nothing serious. There are three possibilities in football - win, draw or lose. Today we have lost, this is not serious. We look ahead.
"It is not always logical. Three days ago we had a great match against Marseille [in the Coupe de la Ligue] and now, we concede defeat. There is not necessarily an explanation. We didn't show our usual aggressiveness. Perhaps this is the explanation."
Les Parisiens resume their Champions League campaign against Dinamo Zagreb on Tuesday.