On Instagram, Alexander-Arnold wrote: "It’s so difficult to find the right words when your head and heart are struggling to accept that someone you care so much about has gone.
"Diogo, your family was your world. They were everything. For Rute, his children, and his parents, all of our hearts are broken. And for Andre as well. Brothers and best friends.
"When it’s less painful, I want to remember Diogo with a big smile. So many laughs and happy moments. He was such a great teammate and a true friend.
"Forever number 20. Rest in peace, Diogo."