Andres Iniesta penned an emotional letter to Fernando Torres as the two prepared to face one another a final time in the Sagan Tosu striker's last professional match.
Torres has announced he will retire from football following Friday's fixture between his Sagan side and Iniesta's Vissel Kobe.
The Spain greats enjoyed international success at the 2010 World Cup and two European Championships, having played together since representing their country at youth level.
Iniesta wrote a lengthy letter to Torres before Friday's game, in which the playmaker netted a penalty before going off injured as Vissel surged into a 3-0 half-time lead, published in El Mundo.
"How weird. Don't tell me it's not, Fernando. It's very strange, I would say beautifully strange," he wrote.
"Here we are both about to play your last game as a professional. I still have some left, but here we are on the other side of the world. It is as if life brought us to Japan to say goodbye.
"Football joined us more than 20 years ago when we were children. Well, you will be forever El Nino. And it will never separate us."
Reflecting on their continued success with Spain while representing rival clubs, Iniesta goes on: "Separated, but always together - and until the last moment.
"Above shirts or clubs, we lived in different cities - you in Madrid and I in Barcelona - but we were never enemies, simply friends who wore a different shirt."
Iniesta, who plays with fellow former Spain star David Villa in Japan, concluded: "It has been a wonderful trip. It has taken us to all corners of the world.
"And look where we are today: in Tosu, you and I playing a football game, one more. But it is not one mor, it is your last game. Who was going to tell us? You face 'El Guaje' Villa and I.
"Then, you will return home. Yours are waiting for you, although you have to know that the ball will be sadder today than yesterday.
"Enjoy everything that comes to you now and be happy. But how strange, Fernando. You haven't left yet and I miss you already."
Torres responded to Iniesta's letter with a Twitter post: "Today I woke up knowing that I play my last game as a professional and thinking that I would face it normally.
"Then I read a friend's letter and I start to get excited... thanks friend, @andresiniesta8."