The Argentina fullback's departure for River Plate was confirmed on Tuesday.
And Acuna posted later in the evening: "Sevillistas, today it's time to close a stage and I want to thank you for these years together. You welcomed me and my family with great affection. We were very happy in this beautiful city, where our daughter Martina was born.
"I want you to know that I always left everything in the field and that it was an honour to have defended this shirt. We went through good and bad moments, but I always left everything on the field to put Sevilla at the top.
"From this great club I also take friends , the love of those who always supported me and the joy of having won an important title with you. I thank my teammates, the club employees and especially you, the fans, for so much affection. They will always be in my heart and as they told us from day one: #nevercaterindas."