Xavi has returned to Barcelona as their new permanent head coach following the sacking of Ronald Koeman.
Koeman's 14-month reign came to an end following Barca's 1-0 defeat to Rayo Vallecano on October 27, with the Dutch tactician failing to convince the Camp Nou board of his long-term value to the cause.
Barca have now turned to another club legend in an effort to steady their ship, with World Cup winner Xavi completing an emotional homecoming as he takes the reins from interim boss Sergi Barjuan.
What's been said?
Al Sadd said in an official club statement: "Club administration have approved the transfer of Xavi to Barcelona after the payment of the value of the penalty clause stipulated in his contract.
"Xavi is considered an important part of our history and we wish him every success in the future."
Xavi's credentials
Xavi is one of the most decorated players in Barca's history, having won 25 trophies at Camp Nou between 1997 and 2015, including eight La Liga titles and the Champions League.
The Spaniard made 767 appearances for the club, a record bettered only by Lionel Messi, and also contributed 85 goals and 185 assists.
Xavi left Barca for Al Sadd in 2015 and retired four years later before becoming the Qatar-based club's permanent manager, and delivered the league title in his second season at the helm.
Al Sadd won five more trophies under the 41-year-old, who has now decided the time is right to head back to Camp Nou, having rejected previous offers from Barca due to a lack of coaching experience.
He had made it clear to reporters that he wanted to head home when fresh rumours of a return to Catalunya surfaced. He said: "I really want to go home. I hope it happens. I have a contract and now the clubs have to negotiate. They already know my position."
Xavi has got his wish, with Barca officials flying to Qatar to thrash out a deal with Al Sadd and their top coaching target before an agreement was finalised.
How big is the task facing Xavi?
Xavi will no doubt be a popular appointment among the Blaugrana faithful, but it will take a monumental effort for him to turn the team's fortunes around following their poor start to the 2021-22 campaign.
Barca have already lost three La Liga games, including a painful Clasico defeat at home to Real, with Koeman having ultimately failed to find the right balance in the squad after seeing Messi, Antoine Griezmann and a number of other key players depart in the summer.
New signings Memphis Depay, Eric Garcia and Sergio Aguero have yet to reach their best levels, and the Catalan club sit ninth in La Liga while also finding themselves in danger of being dumped out of the Champions League at the group stage.
However, Xavi will hope to hit the ground running, with Barca set to take in a trip to Celta Vigo on Saturday before then entering another international break that will give a new boss time to find his feet back in familiar surroundings.