Tommy Robredo advanced to the second round of the Valencia Open by beating fifth-seeded John Isner 7-6 (3), 6-3 on Tuesday.
Defending champion Julia Potter and qualifying medalist Margaret Shirley won first-round matches Monday in the U.S. Women's Mid-Amateur.
It doesn't get much better than first-round matches between Serena Williams and Taylor Townsend, Maria Sharapova and Maria Kirilenko, and Venus Williams and Kimiko Date-Krumm.
Second-seeded Fernando Verdasco of Spain overcame a shaky performance to beat Paul-Henri Mathieu of France 2-6, 6-4, 6-4 and reach the second round at the Topshelf Open on Tuesday.
Seeded women's players Li Na and Agnieszka Radwanska overcame stubborn resistance to win their first-round matches at the Madrid Open on Monday.
Serena Williams brushed aside Belinda Bencic of Switzerland 6-2, 6-1 to open her defense of the Madrid Open title on Sunday, while Maria Sharapova beat Klara Koukalova 6-1, 6-2 in the first round.
Top seed Rafael Nadal, second seed David Ferrer and third seed Andy Murray opened the new tennis season with first round wins on the last day of 2013.
Maria Sharapova and Victoria Azarenka won their first-round matches in dramatic, straight sets, but the real action was in their news conferences afterward.
Heavy rain prevented any play at the Strasbourg International, forcing all seven first-round matches to be postponed to Tuesday.
Former top-five player Tommy Robredo of Spain and Blaz Kavcic of Slovenia won the only first-round matches at the Grand Prix Hassan II on Monday.
The top two seeds in the $125,000 Dallas Tennis Classic were ousted in their first-round matches.
Fifth-seeded Thomaz Bellucci beat Brazilian countryman Guilherme Clezar 7-6 (4), 5-7, 7-6 (1) on Tuesday in the first round of the Brazil Open.
Sloane Stephens is pulling out of the U.S. Fed Cup team's upcoming first-round matches against Italy because of a strained abdominal muscle.
Nicolas Almagro has withdrawn from Spain's Davis Cup first-round matches against Canada because of an injury.
Former finalists Viktor Troicki of Serbia and Finland's Jarkko Nieminen each won first-round matches Tuesday at the Thailand Open.
Top-seeded Mikhail Youzhny of Russia beat Vasek Pospisil of Canada 7-6 (4), 6-1 Tuesday to advance to the second round of the St. Petersburg Open.