That left it ninth in LaLiga and six points off the top, a gap that has since been stretched to nine points.
Sergi Barjuan has been placed in temporary charge until a permanent successor to Koeman is found, and Blaugrana great Xavi is the hot favourite.
The 41-year-old has long been seen as a potential future head coach at Barca, and he is even reported to have turned down two approaches in the past: before Quique Setien was hired to replace Ernesto Valverde, and earlier this year when Joan Laporta reclaimed the presidency.
Laporta addressed the media beside Sergi on Saturday (AEDT) and did little to cool speculation as he spoke of his surety that Xavi will one day coach Barcelona, although the president did at least follow that with the caveat of not knowing when that would be.
But while it seems inevitable that Barca will approach Xavi once again in the coming days, Al Sadd has at least attempted to calm the situation from its side.
A statement posted to Twitter read: "In response to what's circulating recently, the Al Sadd management reaffirms that Xavi has a two-year contract with the club and is fully focused on the team's upcoming matches, to maintain our lead at the top of the league and to defend the title."
In response to what’s circulating recently, the #AlSadd management reaffirms that Xavi has a two-year contract with the club and is fully focused on the team’s upcoming matches, to maintain our lead at the top of the league and to defend the title.#AlwaysAlSadd pic.twitter.com/dJP4g0xZBx— 🏆 #76 Al Sadd SC | نادي السد (@AlsaddSC) October 29, 2021
Xavi came through the ranks at Barca and went on to make 767 appearances for the club during one of its most illustrious periods.
He left for Al Sadd in 2014 and finished his playing career there, before taking over as coach and leading it to seven domestic trophies.
Barca faces Deportivo Alaves at Camp Nou on Sunday (AEDT) and is away to Dynamo Kiev in the UEFA Champions League three days later.