Florida: On the verge of victory, Mardy Fish took a lusty swing and staggered out of the follow-through, his left calf cramping and his ability to continue in doubt.
Three points later he limped into the quarterfinals, the last American standing at the Sony Ericsson Open. A gimpy Fish whacked a service winner on match point to win a grueling duel against Juan Martin del Potro, 7-5, 7-6 (5).
Fish is the lone U.S. player among the 16 men and women in the quarterfinals. At 29, he'll overtake Andy Roddick and become the top-ranked American man for the first time if he defeats No. 6 David Ferrer on Wednesday.