A 1-0 defeat to Rayo Vallecano that left the club ninth in LaLiga sealed his fate and was informed of the club's decision after the match.
It hasn't been a good union with the club in the midst of a financial crisis, their greatest ever player, Lionel Messi, leaving for PSG on a free transfer.
Things got so desperate at one point for the boss that Koeman was even forced to use defender Gerard Pique up front.
Now the search for a replacement is on, with Camp Nou legend Xavi high on the shortlist.
The midfield metronome was one of the key men in creating Barca and Spain's period of dominance between 2008-2014, and has long been linked with a return to manage the club since retiring from playing in 2015.
The 41-year-old is currently working in Qatar with Al Sadd who he's managed since 2019 and has guided them to 34 games unbeaten.
According to journalist Fabrizio Romano, Xavi wants the top job and contact between the two parties was made weeks ago.
This will be good news to a number of Barcelona greats desperate for Xavi to return and manage the team, as revealed in the 2018 documentary Take the Ball, Pass the Ball.
Dani Alves, the most decorated player in the history of football with 43 trophies, had an excellent car analogy for what Xavi's return would mean.
"It's a bit like the best cars," the flying right back said. "[Johan] Cruyff was the first great model, the Mark 1, and Pep [Guardiola] is the Mark 2.
"But I think Xavi will be in the same league when he returns as coach. When he comes back, he'll be the Mark 3."
Messi agreed with his former teammate, saying: "I've got no doubt that he'll be back as a coach one day.
"He deserves the chance because of the type of player he was here. He'll make an amazing manager.
"As a player he saw the whole picture from the pitch, I'm sure from the side-lines he'll see it even clearer."
Xavi has so far picked up five trophies in Qatar, with clips of his Al Sadd side replicating Barca's Tiki-taka style often going viral.
He has since been joined in the Middle East by Santi Cazorla and Andre Ayew as they aim for another title.
Sergio Busquets formed a legendary midfield trio with Xavi and Andres Iniesta, winning five league titles, three Champions Leagues, and a World Cup together and believes Xavi is the right man for the job.
"He'll be back one day, I don't know when but he wants to come back and he has the same football philosophy as Pep," Busquets said.
Former Barca and Spain teammate Victor Valdes agreed, adding: "Barca's future needs to be in the hands of someone with Xavi's talent and vision."
Take the Ball, Pass the Ball focused on Cruyff handing down his philosophy to Guardiola, who oversaw a golden period for the club and has passed on that knowledge to Xavi.
Cruyff's son Jordi, who is now a sporting advisor at Barcelona, talked about his father's admiration for Xavi.
"In my father's mind, he was always 'el listo de la clase' the intelligent one of the class, the clever guy," Cruyff Jr said.
"The only problem will be that when already now everybody is pumping this up, then the pressure's too high.
"But if he follows his way little by little, clam like Pep did, then you're ready for it. And I hope one day Xavi will do that."
Koeman's style of play has received plenty of criticism and some of the long ball tactics has been unpalatable for many of the club's supporters.
Xavi said of Barca's style during the documentary: "We believe in this philosophy, which is improved every year and by each Barca manager.
"But the day things start to go wrong, and let's hope that isn't for another 200 years, but if it happens, we must never consider changing our playing style.
"Our unique philosophy should never change. Never."
Unfortunately for Xavi it already has, the question now is if he can be the man to save it.