Sentence:  Yet when play restarted the Czech was a train that kept on running over Nadal. After breaking Nadal in the opening game of the final set, he went 2-0 up and later took the count to 4-2 with yet another <WSD>emphatic</WSD> ace – one of his 22 throughout. 
Meaning of the word marked with <WSD> tags:  Characterized by emphasis; forceful.