Neymar "seemed tense" during the Champions League final, according to Laurent Fournier, who says the attacker was the "most disappointing" player for Paris Saint-Germain in Lisbon.
Thomas Tuchel's men stood on the cusp of European glory after a thrilling run to this season's final.
Neymar scored in both legs of PSG's last 16 triumph over Borussia Dortmund, which took place before the coronavirus pandemic brought the season grinding to a halt.
The Brazilian picked up from where he left off when the Champions League resumed on August 7, inspiring wins against Atalanta and RB Leipzig in a revised straight knockout format which saw the quarter and semi-finals take place in Portugal.
He had the chances to have a similar impact in the showpiece event at Benfica's Estadio da Luz, but failed to make the most of several clear openings in the final third as Bayern goalkeeper Manuel Neuer produced a man of the match display between the sticks.
Bayern ultimately secured a sixth European title by beating PSG 1-0 on Sunday, with Kingsley Coman grabbing the only goal of the game in the 59th minute.
Neymar was inconsolable after the final whistle, and Fournier believes the weight of expectation on club football's biggest stage ultimately ended up taking its toll on the world's most expensive footballer.
The former PSG boss, who had two spells at Parc Des Princes as a player, told Le Parisien: "We are expecting more players like these two [Neymar and Kylian Mbappe] or even [Angel] Di Maria. I expected a very high level from them.
"It was the moment, the perfect match for them, but I had the impression that they lacked freshness. In the match, Neymar was the most disappointing. He was not the same as against Atalanta or Leipzig.
"It showed on his face. After his free-kick against Leipzig, he was laughing. Facing Munich, he was not. From the beginning, he seemed tense.
"It's normal to be tense when playing a final, I've known that, but it's amazing of him, maybe he put too much pressure on himself. We may have put too much on him."
Fournier went on to bemoan Marco Verratti's injury-enforced absence as he highlighted Bayern's dominance in the middle of the park.
"I thought that [Leandro] Paredes and [Ander] Herrera were going to bring more to the middle, so that they could launch Neymar and Mbappe. I was wrong, it was an illusion," said the Frenchman.
"They didn't get the ball high enough to be aggressive. Undoubtedly Verratti would have contributed more with his creativity. His absence was terrible. The physical impact is important in midfield and we were dominated. We lost the battle in the middle."
Fournier added on PSG's failure to rise to the occasion after reaching the Champions League final for the first time in their history: "Am I disappointed? Yes, because I really believed in it. I was really confident before the game. The quarterfinal and semi-final performances were promising, but in the end, it was only Atalanta and Leipzig.
"Against Bayern, the opponent is different. We were perhaps not ready. We were not used to facing a more aggressive and more skillful team. PSG did not hurt them enough."