Cancels arena session in Peru International tennis finals (6)
I believe the answer is:
annuls
'cancels' is the definition.
(annulling is a kind of cancelling)
'arena session in peru international tennis finals' is the wordplay.
'finals' indicates one should take the final letters (the final letters).
The last letters of 'arena session in peru international tennis' are 'ANNULS'.
(Other definitions for annuls that I've seen before include "Repeals or rescinds" , "Cancels officially" , "Declares invalid" , "Cancels, makes void" , "Cancels, abolishes" .)