Playing again at No. 1, Serena Williams routed Flavia Pennetta of Italy 6-1, 6-1 Thursday in the second round of the Sony Open.
This is Williams' first tournament since she regained the No. 1 ranking at the Qatar Open. Williams lost the Doha final to Victoria Azarenka but overtook her for the top ranking the week of Feb. 11.
Sloane Stephens was blanked in the first set but beat Olga Govortsova of Belarus 0-6, 6-4, 6-4. Stephens is ranked 16th, the highest-ranked American after Williams.
Poland's Agnieszka Radwanska, the defending champion who is seeded fourth, defeated Taiwan's Su-Wei Hsieh 6-3, 6-2 in the second round.