United fans excited by rising score in tie? Quite the opposite! (8)

I believe the answer is:

unfasten

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

'tie? quite the opposite' is the definition.
I can't tell whether this definition defines the answer.

'united fans excited by rising score' is the wordplay.
'united' becomes 'U' (abbreviation).
'excited' indicates an anagram.
'by rising score' becomes 'ten' (I can't explain this - if you can you should believe this answer much more).
'fans' anagrammed gives 'nfas'.
'u'+'nfas'+'ten'='UNFASTEN'

'in' acts as a link.

Can you help me to learn more?

(Other definitions for unfasten that I've seen before include "Loosen or open, say seatbelt" , "tie? No" , "Nun's fate (anag.)" , "Unlock" , "Let go" .)

I've seen this clue in The Times.

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.