Les Parisiens boss says that his team must be prepared to come up against sides determined to beat them every week after PSG came from behind to defeat Bordeaux on Saturday.
Les Rouge-et-Bleu fell behind to Henri Saivet's first-half strike and looked to be heading for defeat before late goals from Hervin Ongenda and Alex, the latter in the fifth minute of stoppage time, earned them the victory in the Gabonese capital of Libreville.
Blanc admitted to being satisfied with securing the first piece of silverware of the season but his joy was tinged with relief, acknowledging that the manner of the win showed that his team will face a battle every time they play in Ligue 1 this season.
"The reaction of the players [in overturning a 1-0 deficit] does not hide the negative," Blanc told journalists after the game. "I told the players that the goal was to win, and the goal was met. It was very hard to do. We had a glimpse of what awaits us this season, teams will be super motivated against PSG, but this is normal.
"When a team defends well as Bordeaux did and then scores, it motivates them and it becomes difficult to get back into the game."
Blanc, who won a league and cup double as Bordeaux coach in 2009, was also quick to praise his former club and their contribution to the fixture.
"In the first half, Bordeaux certainly rushed us and had opportunities to open the scoring," Blanc said. "Gradually, Bordeaux gained confidence and scored a beautiful goal due to a lot of passivity in our defense.
"At halftime, there was a little speech, which helped balance the team and tactically we changed a few things. The entry of three players 20 minutes from the end gave more speed and depth.
"It allowed us to believe in our chances. When there was a free kick at the end, I think there are a lot of players who believed that PSG would score.
"I am happy as the players won a trophy. I hope there will be others, but this will be difficult, as we have seen tonight. Do not believe that when PSG enter the field, the game is already won."
PSG begins the defense of its Ligue 1 title against Montpellier on Aug. 9.