Antoine Griezmann apologised to Atletico Madrid fans for the "damage" he may have done when initially leaving the club for Barcelona in 2019.
Griezmann joined Barca in 2019 when the Catalans triggered his €120million release clause, ending a long courtship by the Blaugrana.
Barca had been heavily linked with Griezmann in 2018, but the player opted to remain with Atletico, making his announcement in a documentary called 'La Decision'.
Although Griezmann stayed then, many Atletico fans were frustrated by his conduct, with the documentary – echoing his NBA hero LeBron James' 'The Decision' – seen by some as an unnecessary sideshow that stoked speculation.
The France forward ended up joining Barca the following year, but his spell at Camp Nou was generally underwhelming, and he returned to Atletico last season on loan, a deal that was made permanent on Monday.
In his first LaLiga game since signing a permanent deal with Atletico, Griezmann scored the winner in a 1-0 win at Athletic Bilbao to take his league tally for the club to 100, and afterwards he felt it necessary to offer an olive branch to supporters.
"In the end, I want to apologise," he said.
"I know that people want to hear it from my mouth: I apologise for the damage I may have done to fans.
"But the greatest forgiveness I want to ask for is on the pitch, giving everything for the team and with [games] like this."
Atletico completed the signing of Griezmann after opting to tread carefully with the amount of minutes he was being given earlier this season.
According to reports, Atletico would have been obliged to pay €40m for Griezmann if he had played more than 30 minutes in a certain percentage of their games.
As such, Diego Simeone routinely brought Griezmann on after the 60th minute, and in the end that tactic seemingly forced Barca to accept a significantly reduced deal apparently worth just under €20m.
"Personally, it was complicated, but I tried not to show it," Griezmann said of the contractual quirk.
"I know I was playing for a coach I love very much and some team-mates who deserve the best of me.
"If I have to play, I give 100 per cent, and if I don't [play], I encourage my team-mates. Then, when I come on, I try to make a difference."