I've been there, I know. You can have all the experience you like, but there comes a time when your brain starts to write cheques your legs can't cash.
You start trying to compensate - but you over compensate.
You either get too close and get turned or you hang back because you'll get skinned, you think need those extra yards...
and you still get skinned, if the winger has the space to push it behind you and because you're not up his backside...in the football sense...he doesn't even have to come off you to receive the ball. etc, etc etc.
Dixon is a full back and can supposedly, put a bit of a tackle in. He presumably knows the basics...the ball can get past you, or the man can get past you - But Not BOTH!
And allegedly - lightening fast, which is not the end of the world in a defender when faced with a trick fast winger.
Dixon may not be CAFU 2.O but he's got to have a better chance than Young & Holgate at catching / keeping up with, maybe even get a foot in on Son or whoever while having enough pace not to have to pull him back.
You learn by doing.