Andy Roddick reached his second quarterfinal of the year with a 6-4, 7-5 victory over Denis Istomin of Uzbekistan at the Delray Beach International Tennis Championship Thursday. Roddick avenged his loss to Istomin — in his other 2012 quarterfinal appearance — at last month's San Jose tournament. Roddick is currently ranked No. 30. He's been dealing with hamstring and ankle problems this year. Roddick only got half his first serves in against the 51st-ranked Istomin. In the second set, Istomin led the penultimate game 40-15 but then made four consecutive unforced errors to hand Roddick the service break. Roddick eventually managed to serve out the match in the next game, but only after seeing off three break points and needing two match points. Roddick will play seventh-seeded Kevin Anderson of South Africa in the quarterfinals. Anderson topped Xavier Malisse of Belgium 6-3, 3-6, 6-3. The 2.01-meter (6-foot-8) Anderson had nine aces and won 77 percent of his first serve points, although his first serve percentage was only 55 percent. Fifth-seeded Philipp Kohlschreiber of Germany also advanced to Friday's quarterfinals. He defeated 57th-ranked Ivan Dodig of Croatia 6-2, 6-2. The German's quarterfinal opponent will be Dudi Sela of Israel, who earned his quarterfinal spot with a 6-4, 6-4 win over Jarkko Nieminen of Finland. Radwanska pulls out In Malaysia, top-seeded Agnieszka Radwanska of Poland withdrew Friday from the Malaysian Open due to a right elbow injury, giving Taiwan's Hsieh Su-Wei an easy path to the semifinals. Meanwhile, fifth-seeded Petra Martic of Croatia bounced back from a set down to upset third-seeded Peng Shuai of China 4-6, 7-6 (3), 6-4 at the Bukit Kiara Equestrian and Country Resort.
