The Slovenia international sealed his move to Old Trafford on Saturday, signing from RB Leipzig on a contract until June 2030.
Sesko, our fourth senior incoming of the summer, was introduced to the home faithful before the Snapdragon Cup match against Fiorentina after Matheus Cunha, Diego Leon and Bryan Mbeumo had also taken their bows.
Cunha (no.10) and Mbeumo (no.19) have already been given their numbers, while Leon has now changed to no.35, following Sesko's arrival.
Leon sported the no.30 during each of his pre-season appearances, while the jersey has previously been worn by the likes of Wes Brown and John O'Shea.