The 21-year-old expressed gratitude for the trust Alonso placed in him during their time together in La Liga.
"It was exactly what I was looking for, honestly. Now he's signed for Chelsea.
I hope everything goes well for him. Of course, we're still messaging each other," Guler added.
The Turkish international revealed details of Alonso's coaching methodology, noting that the manager personally contacted him after a standout Champions League quarter-final performance.
"After the match against Bayern Munich [in the Champions League quarter-finals], he told me he was very proud of me," Guler recalled.
Guler also shared insights on his tactical positioning under Alonso, who envisioned him playing centrally rather than out wide.
This adjustment allowed him to adapt quickly and perform comfortably in his natural role.
"During [Jorge] Jesus's time at Fenerbahçe, I played on the right wing. I continued there with Ancelotti as well, because there were many players in the center.
Xabi Alonso, before arriving, spoke to me and told me he was thinking of me for the center.
I was very happy because that's the position I've felt most comfortable in since I was a child.
It was exactly the role I wanted, and it didn't take me long to adapt," Guler explained.
The midfielder also highlighted specific instructions from Alonso ahead of his first start of the season.
"Before our first match, when I was in the starting 11, he told me that morning, 'I want you to touch the ball more than everyone on your right.'
