Sentence:  Gillespie was reminded he had promised to join team-mate Matthew Hayden in a nude lap of the ground if he <WSD>converted</WSD> his century into a double. 
Meaning of the word marked with <WSD> tags:  To increase one's individual score, especially from 50 runs (a fifty) to 100 runs (a century), or from a century to a double or triple century.