The Slovakian prodigy has managed eight top-five finishes in this Tour so far but after 12 stages he has yet to cross the finish line, a frustration he attributes to his rivals' defensive tactics.
The 24-year-old former cyclo-cross and mountain bike racer, who won three Tour stages in 2012 and one last year, has enjoyed an encouraging opening week to take possession of the green jersey as the points classification leader but has also admitted that he it has been a frustrating race.
"They know that I'm faster than them in a finish in a little group so nobody wants to co-operate," said Sagan who finished in second place yesterday following a ninth-place finish on Wednesday..
His rivals "sandbagged" him at the denouement of that stage - No.11 of the Tour - which was won by French rider Tony Gallopin. The Australian Michael Rogers and Pole Michal Kwiatkowski both refused to take turns with Sagan as Gallopin attacked 2.5 kilometres from the line, with the pair fully aware that the Slovakian was likely to beat them in the final sprint.
It was a similar story yesterday when Norway's Alexander Kristoff claimed his maiden Tour victory, beating Sagan in a sprint on the 12th stage - a 185.5-km ride from Bourg en Bresse. Kristoff, who rides for Katusha, timed his effort perfectly to win with a comfortable margin which leaves Sagan awaiting a win. "The Tour is against me," he said.
Sagan, however, has been showing signs of nerves this year by attacking too early, which means he sometimes lacks energy in the final straight. That was not the case yesterday, of course, when he was beaten fair and square by Kristoff.
Stefano Zanatta, the Cannondale sports director, has since acknowledged that the Slovakian's objective was to win the green jersey. "It is very good for the green jersey. Kristoff did a great sprint," said Zanatta.
"Peter did his maximum, he is always around. The morale is good. He cannot always win and he has to accept that."
Barring crashes or abandon, Sagan should secure the green jersey for the third year in succession. He has 341 points in the classification, with second-place Bryan Coquard of France on 191, albeit Sagan would dearly love to add a stage victory.