RIO DE JANEIRO, June 26 (Xinhua) -- Copa America organizers said on Tuesday that they believe the ongoing 2019 tournament is progressing well, despite an apparent abundance of empty seats in stadiums and players' criticism over the state of some of the pitches.

Just 2,100 supporters paid to see Monday night's clash in Belo Horizonte between Japan and Ecuador, while another 7,600 spectators watched the game free of charge.

"There is a balance between what one can charge and the cost of the event," said Thiago Jannuzzi, general manager of the organizing committee, who insisted the policy for setting ticket prices was correct.

"It was all successful. We are receiving important revenue to balance our costs. Getting that right is essential," he continued. "Prices will not be reduced to avoid empty seats and we have prices that are very accessible."

Organizers said some tickets cost as little as 15 U.S. dollars, similar to the price of popular seats for Brazilian league matches.

They also dismissed claims of a "structural problem" with the tournament, following criticism of the pitches at four venues from several players, including Argentina's Lionel Messi.

Rio de Janeiro's Maracana, Belo Horizonte's Mineirao, Porto Alegre's Arena do Gremio and Salvador's Fonte Nova stadiums were all said to have bumpy playing surfaces.