#2 Tough times for Trent Alexander-Arnold
Alexander-Arnold came to the fore last season, particularly in the two-legged quarter-final against Manchester City, where he quietened Leroy Sane and impressed in general. Joe Gomez's injury made it seem like Alexander-Arnold had cemented his spot, but that has changed in recent weeks.
Despite his athleticism and attacking inputs, Alexander-Arnold has been found wanting defensively this season. He was partly at fault for Arsenal's goal at the weekend, and he was taken off at half-time in Belgrade to be replaced by Gomez.
Gomez has emerged as a more assured and mature defender, and his versatility means that he's above Alexander-Arnold in the pecking order. Nathaniel Clyne can also fill his position which casts further doubt upon his starts. That being said, his potential and willingness to learn are clear, so odds are that he will bounce back strongly.