New side, after old team get rusty (7)

I believe the answer is:

oxidise

I'm a little stuck... Click here to teach me more about this clue!

'get rusty' is the definition.
I can't tell whether this definition defines the answer.

'new side after old team' is the wordplay.
'new' indicates an anagram.
'after' says to put letters next to each other.
'old' becomes 'o' (abbreviation).
'team' becomes 'XI' (a football team, from Roman numerals for 11).
'side' anagrammed gives 'dise'.
'o'+'xi'='oxi'
'dise' after 'oxi' is 'OXIDISE'.

Can you help me to learn more?

(Other definitions for oxidise that I've seen before include "Eg, go rusty" , "Eg, rust (S, not Z)" , "Combine chemically with a particular gas - ie six do (anag)" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.