Heavily rely on us going off chasing love (9)

I believe the answer is:

onerously

'heavily' is the definition.
(thesaurus)

'rely on us going off chasing love' is the wordplay.
'going off' indicates an anagram (letters go or move around).
'chasing' is a charade indicator (letters next to each other) (some letters chase after others).
'love' becomes 'o' (love means zero in tennis).
'rely'+'on'+'us'='relyonus'
'relyonus' anagrammed gives 'nerously'.
'nerously' put after 'o' is 'ONEROUSLY'.

I've seen this clue in The Independent.

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