Laurent Blanc's men completed a league double over arch-rivals Marseille last Sunday, but PSG's preparations for the trip to Corsica have been disrupted with many of the club's players away on international duty in midweek.
Sirigu was part of the Italy squad that lost 1-0 to Spain on Wednesday and is now relishing switching his attentions back to club football for the Bastia clash.
"It's always difficult to prepare for a game while many players are returning from international duty," Sirigu told PSG TV.
"A lot of us have travelled, and therefore have not yet trained together. The trip to Bastia will be even more difficult.
"I think you have to give 100 per cent to prepare for this match.
"We must no longer think of the national teams, but go back to where we left off after the match against Marseille and act is if we had not gone. The focus should be on Paris Saint-Germain."
PSG are eight points clear at the top of Ligue 1 and will be heavy favourites against a Bastia team they have not lost to since 2003.
‘Arteta, Alonso, Emery, me… none of us were physical players – we needed the understanding of the game. That probably helped us move into management’: Premier League boss reveals reasons for natural career progression
‘England have the players to win the World Cup – it’ll be tough for Thomas Tuchel to do a bad job, with the squad he has at his disposal’ Former Three Lions winger backs new boss after gentle qualifying draw
