Lionel Messi has targeted Champions League glory with Paris Saint-Germain after finalising a "complicated" exit from Barcelona.

The Argentina international's 21-year association with Barca officially ended on Tuesday when joining PSG on a two-year deal with the option of a third.

Six-time Ballon d'Or winner Messi looked certain to sign a new long-term deal at Camp Nou, but financial complications at the LaLiga club forced him out of the door.

Less than a week after Barca announced the 34-year-old was to leave, he was unveiled as a PSG player at the Parc des Princes on Wednesday.

Reflecting on a whirlwind week, Messi admits it was difficult departing the only club that he has represented in his career to date.

"It's been a very hard moment after so many years," he said at a news conference. "It was a difficult change after so much time. But the moment I arrived here I felt very happy. 

"I'm really enjoying my time in Paris and want to begin training now, starting this new moment in my life.

"The club were really quick with negotiations. It's been a really easy process, even if it was a tricky situation. I want to thank them for sorting out any problems."

He added: "Everything that happened to me this week has been very strange. It's been emotional. I can't forget what I lived and experienced at Barcelona.

"But I feel impatient and ready for this new life with my family. I'm very happy. This whole week I've been going through up and downs, but we are processing all of this little by little every day. 

"I was in Barcelona when the press talked about the move. The people in Paris were already outside. It was incredible to see them in the streets. I really want to see them in the city, in the stadium. It will be an incredible year."

Messi departs Barcelona having scored 672 goals and assisted 265 more for the Catalan giants across 778 appearances.

He won 35 trophies at Camp Nou, including four Champions League triumphs.

PSG have never won the competition, coming closest to doing so last year when losing to Bayern Munich in the final, but Messi is hopeful of lifting the famous trophy once again.

"I still want to play and I still want to win, as I did at start of my career," he said of his ambitions with the French giants. "This club it is ready to fight for all the trophies.

"That is my goal. I want to keep growing and winning titles. That's why I came here to this club. I hope we can make it happen."

Asked specifically about PSG's Champions League hopes, Messi said: "This team is ready. There are some new transfers, but they have been close and are ready to win it.

"I have just come here to help. My dream is to win this trophy again and I think Paris is the best place to do so.

"It was very complicated to exit Barcelona without knowing where I would go. Barcelona was my home since I was a kid. 

"I knew I'd arrive in a strong team that was aiming to win the Champions League, which I love to win. I know my goals and Paris' goals are the same. 

"It's difficult to win it, you need a strong group. Luck is also a factor. Sometimes the best team in the world does not win. We want to win the Champions League."

Messi may cross paths with Barcelona in UEFA's showpiece competition this coming campaign, potentially giving the superstar forward a chance to sign off at Camp Nou in front of supporters.

"It would be very nice to go back, hopefully with fans," Messi said. "It would be very strange to play at home, there in Barcelona, in another shirt, but it could happen."