Summarise extraordinary race on page (5)
I believe the answer is:
recap
'summarise' is the definition.
(I've seen this before)
'extraordinary race on page' is the wordplay.
'extraordinary' is an anagram indicator.
'on' says to put letters next to each other.
'page' becomes 'p'.
'race' anagrammed gives 'reca'.
'reca'+'p'='RECAP'
(Other definitions for recap that I've seen before include "In brief, go over the main points again" , "Epitomize" , "In summary, state again" , "Go over again; summarise" , "Summary (abbr.)" .)