Russian agreed communist rose to the challenge (5)
I believe the answer is:
dared
'rose to the challenge' is the definition.
(dared to do something challenging)
'russian agreed communist' is the wordplay.
'russian agreed' becomes 'da' ('yes' or 'agreed' in Russian).
'communist' becomes 'red' (red can informally mean communist).
'da'+'red'='DARED'
(Other definitions for dared that I've seen before include "Challenged - was audacious" , "Defied, challenged" , "Ventured" , "Took a risk" , "was bold enough" .)