Loris Karius says he had to convince Jurgen Klopp to let him join Besiktas as the Liverpool manager was keen on keeping him at Anfield for the season.
Karius was unveiled as a Besiktas player on Wednesday, having joined the Turkish side on a two-year loan deal that could become permanent if certain performance criteria are met.
He had lost his place as Liverpool's No. 1 following the arrival of Alisson, with the German keen on securing game time after his nightmare performance in the Champions League final.
"He [Klopp] told me he would like to have me in the squad because he wants to have the best quality players," Karius said. "But I spoke to him and asked him for my wish. It is important to me to play for Besiktas.
"I talked with him for a long time and he understood my situation. I think it was a good deal for everyone. He wished me well but he said he would have liked to keep me."
Karius' future at Liverpool was in doubt after his errors directly led to two Real Madrid goals as part of the 3-1 defeat in Kiev in May. Klopp said Karius had suffered concussion after sustaining a blow to the head from Sergio Ramos.
"If you give the circumstances with a serious injury, as well that I don't know in what way it affected me, you have to move on," Karius added. "It was an unlucky day, but it's football.
"I don't think a lot of players reach a Champions League final. If you look at how many goalkeepers in the league reach a Champions League final, I don't know. So it was a great achievement.
"Unfortunately, on this day we were unlucky and it wasn't the best performance. But there were a lot of things that came together. It's in the past now and I look forward to the future."
Karius' departure means Simon Mignolet will spend the 2018-19 season as Alisson's deputy.
However, there could be further departures from Liverpool before the close of the European transfer window on Friday.
Lazar Markovic is expected to leave, sources have told ESPN FC, and Divock Origi will depart if Liverpool receive an offer close to their £27 million asking price.
Borussia Dortmund were interested in Origi, but Liverpool broke off talks with the Bundesliga side due to their reluctance to sanction a loan move for the striker.
Meanwhile, Sheyi Ojo has joined Stade Reims on a season-long loan after first signing a new contract with Liverpool.