(CNN) Manchester City chairman Khaldoon Al Mubarak says smears against the club are borne out of jealousy.

City dominated at home this season, winning the domestic treble -- the first English men's team to do so.

In the process, it became the first club in 10 years to retain the English Premier League title.

However, success on the pitch has been marred by controversy off it -- including a UEFA investigation into allegations of unfair financial practices.

"With success, there is a certain level of jealousy, envy, whatever you call it. That's part of the game," Mubarak said in his season review with the club website , denying any financial wrongdoing.

"When Manchester United dominated the Premier League for many years, they know what they had to deal with for so many years. That's part of the game. It's not easy for our competition, we know that."

Manchester City chairman Khaldoon Al Mubarak (left) poses with Pep Guardiola after winning EPL title.

Manager Pep Guardiola has produced a winning machine at the Etihad Stadium since joining in 2016, but Mubarak rejects suggestions the club has bought such success.

Despite possessing some of the best players in the world, City does not have a single player in the top 10 most expensive signings.

"The reality is, we didn't buy the most expensive player in the Premier League, we didn't buy the most expensive goalkeeper, we didn't buy the most expensive defender, we didn't buy the most expensive midfielder, we didn't buy the most expensive striker," said Mubarak.

"Look at the facts, let's talk about facts."

Despite the club facing a possible ban from the Champions League, Mubarak is "comfortable" with the UEFA investigation, for now.

"If the process is going to be judged on facts, then unquestionably we will prevail. If it's not about facts, and it's about other things, then it's a different conversation."

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'Ugly' and 'disturbing'

In his interview with the club, Mubarak also responded to claims reportedly made by Spanish La Liga president Javier Tebas that City, backed by Abu Dhabi United Group, and PSG, owned by Qatar Sports Investments, were " playthings of a state " run off petrol and gas.

"I think there's something deeply wrong in bringing ethnicity into the conversation," Mubarak said, responding to the comments made by Tebas at FT's Business of Football summit

"This is just ugly, I think the way he is combining teams just because of ethnicity. I find that very disturbing, to be honest."

The La Liga president reportedly accused City of distorting the transfer market with its financial might, a comment refuted by Mubarak.

"In football, people know what Tebas is about...He plays the role of a politician," he said.

"You can't take him too seriously. There is credibility when it comes to people and I think he distorts facts."

Commenting on the amount of money spent by La Liga clubs in recent years, the City chairman added: "There is a hypocrisy in this statement that is ironic.

"At the time of breaking records on player acquisitions, I mean -- who started that?" Mubarak said.

"The world records, Figo and Zidane, these huge jumps in these transfers. Where did they happen?

"People with glass homes, shouldn't be throwing rocks."

Manchester city owner Sheikh Mansour bin Zayed Al Nahyan looks on during his club's match against Liverpool in 2010.

Mubarak says Tebas' comments are not just an attack on the club but also the EPL.

He believes the fact that four English clubs are in the two European cup finals this season "bothers" many people.

"We have to be protecting that, we have the best league in the world. We have the most commercial league in the world, we have the most successful clubs...This is a special league," he said.

"This attack is not just on Manchester City, this attack is against this league. I hope people start seeing that."

La Liga did not immediately respond to CNN's request to comment.