Neymar claims he and his Argentine teammate and friend Lionel Messi "lived hell" at Paris Saint-Germain, which they both left at the end of last season.
The Brazilian, who has joined Al-Hilal in Saudi Arabia, said he was "very happy" that Messi, who has been at Inter Miami in the United States since June, won the 2022 World Cup with Argentina.
However, he added in an interview with Brazilian television channel Globo on Sunday, "He (Messi) has experienced both sides of the coin."
"He went to heaven with Argentina, he won everything in recent years, and with Paris he lived hell, we lived hell, him and I," said Neymar, 31, who spent six seasons at PSG, winning five Ligue 1 titles but who, like Messi, was sometimes booed by the Parc des Princes crowd.
"We got angry because we weren't there for that, we were there to give our best, to be champions, that's why we came back to play together, we came back together to make history," Neymar said, who had already played with Messi at Barcelona.
"Unfortunately, we didn't succeed," he regretted.
PSG, despite the sums invested by its Qatari owner and the salaries offered to Messi and Neymar, has still not achieved its stated goal of winning the Champions League.
Neymar, who signed a two-year contract with Al-Hilal for a transfer of around 100 million euros, including bonuses, has been called up for Brazil's first two matches in the 2026 World Cup qualifiers against Bolivia on September 8 in Belém (north) and Peru on September 12 in Lima.
Analysis:
Neymar's comments are a damning indictment of his time at PSG. He and Messi were two of the biggest names in world football, but they were unable to achieve their goal of winning the Champions League. Neymar's frustration is understandable, but his comments are also a reflection of the high expectations that were placed on him and Messi.
It remains to be seen whether Neymar will be able to achieve more success at Al-Hilal. The Saudi Arabian club is a major spender in the transfer market, and they will be hoping that Neymar can help them win more trophies.