Barcelona coach Xavi Hernandez said on Saturday it was a huge disappointment that winger Ousmane Dembele decided to leave and sign for Paris Saint-Germain.

The French side confirmed Dembele's arrival earlier on Saturday, activating a €50-million clause in his contract to sign the 26-year-old.

Xavi defended Dembele against criticism and frequently hailed the winger, who became a key player in their LaLiga triumph last season after years of struggle at the club following his 2017 arrival.

"For me he was a good kid, a kid who helped us a lot, we made him important, for me he was an important player," Xavi told a news conference.

"In the end it was a big disappointment, a big disappointment that he decided to go when here he had happiness.

"We bet on him and it's disappointing for me on a personal level. I think that there was a project here, but he chose to go elsewhere.

"I wish him luck, but in general, it has been disappointing, I would say."

Dembele signed for Barcelona from Borussia Dortmund six years ago for what was a club record fee of €105 million.

Injuries plagued the 2018 World Cup winner and it was not until Xavi's arrival that he found consistency at Barcelona.

The Spanish champions start their La Liga title defence on Sunday at Getafe.

Dembele's departure and a financial agreement announced on Friday for €120 million to sell a third of shares in the club's digital platform Barca Vision, mean the club were able to register new signing Ilkay Gundogan's contract with LaLiga.

Barca also registered defender Ronald Araujo's renewed deal with the Spanish league.

Other players are yet to be registered but Xavi said he was confident he would have almost everybody available against Getafe.

"I'm 90 percent sure of having almost everyone," said the coach.

"Everyone is a making a big effort, we're optimistic."