The principality club had entered Friday's match having won their opening two fixtures of the French league season but were held out by a dour Toulouse side, who did not manage a shot on target at Monaco's Stade Louis II.
While Toulouse's defensive structure was tough to break down, Ranieri claimed his players' impatience in the second half was critical in their inability to score.
The 61-year-old Italian coach said Monaco played well before half-time but that individuals tried to do too much by themselves after the break.
"During the first half we were playing as a team, left, right, everything was done well," Ranieri said.
"In the second half, the players wanted to dribble; they wanted to do something extra, more than was necessary."
The result sent Monaco one point clear at the top of the Ligue 1 table but they will probably drop below at least one of Lyon, Marseille and Saint Etienne by the end of the weekend.
Lyon, Marseille and Saint-Etienne are all on six points, one behind Monaco, and a win for any of those three clubs will take them ahead of Ranieri's team.
Ranieri bemoaned the fact his team had to play in front of an empty stadium as Monaco's fans were locked out as punishment for a pitch invasion in Ligue 2 last season.
"Without the atmosphere, the fans, it is very difficult to play," Ranieri said.
When asked why, Ranieri explained: "Because the payers get used to playing with the fans and their support."
"It was very difficult to play without their support, they help us."
