Coach Aliou Cisse was critical of his pacy and powerful side after their 2-2 draw with Japan on Sunday, saying their opponents were the better team, and called on forward Mane to step it up.
"Frankly, we were not very good," concluded Cisse, Senegal captain in their run to the quarter-finals in 2002, their only previous appearance at a World Cup.
Cisse was particularly unhappy with the way that Senegal twice threw away the lead in Yekaterinburg.
Substitute Keisuke Honda's leveller, 12 minutes from time, was an especially poor goal to give away as goalkeeper Khadim N'Diaye flapped at a cross.
Victory would have all but propelled Senegal into the last 16, but they now face a Colombia side in Samara who have their tails up following a classy 3-0 win over abject Poland.
Going into the final round of games in Group H, Japan and Senegal have four points, Colombia have three and pointless Poland are already eliminated.
It means that a draw for Cisse's side will be enough to progress.
Belgium and England await whichever two teams make it out of Group H.
Senegal were far from convincing against Japan and even though Mane scored the opener it had a large dose of good luck about it.
The 26-year-old, coming off the back of a successful season at Anfield that saw Liverpool reach the Champions League final, was peripheral after that.
Cisse, who needs to find a way to get Mane more involved, was unimpressed.
"A player like Sadio Mane is a player with a lot of expectations and he is one of the players under the spotlight," said Cisse.
"He can do better, but today he was better than against Poland and he needs to do better against Colombia."
If there was something of a negative vibe around Senegal, Colombia are going in the opposite direction.
They became the first South American side to lose to an Asian one at a World Cup when they were beaten 2-1 by Japan in their opener.
But there were mitigating circumstances -- they played most of the game with 10 men after Carlos Sanchez was dismissed for handball.
Colombia coach Jose Pekerman was also unable to call on the services of the injured James Rodriguez from the start.
But the midfielder, one of the stars of the World Cup four years ago, when Colombia marched to the quarter-finals, returned against the poor Poles with an impressive performance.
Radamel Falcao, Yerry Mina and Juan Cuadrado all scored in a stylish victory, but Pekerman hinted afterwards that he might tinker for Senegal.
"When I make the starting line-up, I do it taking account of the whole context in which we find ourselves," the Argentine said.