They booed when Russia's Evgeny Tishchenko was named the Olympic heavyweight boxing champion, they booed during the medal ceremony, and they booed before and after the Russian anthem was played.
Spectators protested with disbelief Monday when gold was awarded to the reigning world champion after his Olympic bout with Kazakh boxer Vassiliy Levit.
The three judges counted 29-28, 29-28 and 29-28 in favour of the Russian, but the result belied the impression of fans and reporters that former kickboxer Levit was the more active hitter over wide stretches of the three rounds.
The Kazakh with the shaved head started the bout with relentless attacks, while the taller Russian kept his cool and hit back with blows to the head in between the pummeling.
While the judges saw Levit ahead early, their scores put Tishchenko in the lead after the first break, even though he seemed to be on the defensive, getting punched into the ropes in the second round.
In the third, the 28-year-old Levit briefly brought Tishchenko to the ground.
The 25-year-old Russian spent a long time in the corner to be treated for a cut, but when he came back, he dealt a few strong blows to Levit in the final seconds of the match.
"I was thinking that I won," Levit told reporters, summing up his feelings just before the winner was announced. "But you see how it ended up."
The crowd in the sparsely filled arena clearly sided with the Kazakh, who was seen as the underdog despite his current Asian champion title. People roared with anger and shouted "Kazakhstan! Kazakshstan!" long after it had become clear that the Kazakh won only silver.
"It is really a pity that people on the stands reacted like that," Tischchenko said.
"Maybe things looked different from the side.
"The judges gave me the medal, so they had a reason for it," he concluded.
In the semis, Levit had beat another gold contender, Cuban Erislandy Savon, who earned bronze.
Uzbek boxer Rustam Tulaganov took the second bronze medal after losing to Tishchenko.