Zverev reaches second straight Challenger final

   Mischa Zverev will get another crack at a Challenger title in Northern California.
   The unseeded German defeated eighth-seeded Bobby Reynolds of Acworth, Ga., 6-4, 6-3 Saturday in the semifinals of the $100,000 First Republic Bank Tiburon (Calif.) Challenger at the Tiburon Peninsula Club.
   Zverev, a 25-year-old left-hander originally from Moscow, lost to James Blake 6-1, 1-6, 6-4 in the final of last week's $100,000 RelyAid Natomas Challenger in Sacramento.
   Zverev will face unseeded Jack Sock for the first time today at 2 p.m. or later for the Tiburon title. Sock, 20, beat fellow American Steve Johnson 6-4, 7-6 (4) to gain his first Challenger singles final.
   Zverev, a veteran of the elite ATP World Tour, is ranked No. 153 in the world after reaching a career-high No. 45 in the world in 2009 and then battling injuries. He has advanced to one final on the elite ATP World Tour (Metz in 2010) and won four Challenger singles titles (most recently in 2007).
   Sock is ranked No. 220, down from his career high of No. 206 last month. He has won two U.S. Open titles, boys singles two years ago and mixed doubles last year with Melanie Oudin.
   In the Tiburon doubles semifinals, fourth-seeded Rik de Voest of South Africa and defending champion Chris Guccione of Australia edged top-seeded Robert Farah of Colombia and Johnson 6-7 (3), 6-3, 10-6 tiebreak. Farah and Johnson were teammates at USC for two years.
   De Voest and Guccione will play second-seeded Jordan Kerr of Australia and Andreas Siljestrom, 6-foot-9, of Sweden today at noon for the title. Kerr and Siljestrom topped Alex Kuznetsov of the United States and Zverev 6-3, 7-5.