Celebratory test includes universal speed (9)

I believe the answer is:

triumphal

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'celebratory' is the definition.
Both the definition and answer are adjectives.
Perhaps you can see an association between them that I don't see?

'test includes universal speed' is the wordplay.
'test' becomes 'trial' (synonyms).
'includes' is an insertion indicator.
'universal' becomes 'u'.
'speed' becomes 'mph' (miles per hour).
'u'+'mph'='umph'
'trial' going around 'umph' is 'TRIUMPHAL'.

Can you help me to learn more?

(Other definitions for triumphal that I've seen before include "Exulting in success" , "Celebrating a victory" , "Exultant" , "Showing excessive exultation" , "Scenting victory" .)

I've seen this clue in The Daily Express.

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