SOFIA, Bulgaria (AP) - Toccara Montgomery of the United States won her fourth straight match with a pin Saturday and advanced to the finals of  the wrestling world championships.     In the men's competition, Joe Williams of the United States narrowly missed a spot in the 168-pound finals. He was beaten was Russia's Buvaisa Saitiev, an Olympic and three-time world champion.     Montgomery pinned Russia's Sveta Yaroshevich in 3 minutes, 12 seconds in the semifinals of the 150-pound category. She was to face Canada's Christine Nordhagen, last year's world champion, for the gold medal later in the day.     Nordhagen defeated Germany's Anita Schatzle 10-4 in the second semifinal.     In other semifinals, Russia's Lyubov Volosova ousted Tatyana Lazareva of Ukraine 4-2 in the women's 123-pound category. Lazareva won a silver medal at the 2000 world championships.     Volosova next meets defending world champion Seiko Yamamotu of Japan, who pinned Lee Na Lae of South Korea for a 6-0 victory to advance to the finals.     Irina Melnik, Ukraine's reigning world champion in the women's 101-pound class, won the right to defend her title by defeating Germany's Brigitte Wagner 5-1.     Williams, a newcomer to the U.S. team, lost 5-4 to Saitiev. Making a last-ditch effort at winning, the American brought down Saitiev with a spectacular throw, but the judges ruled he had stepped outside the mat.     Saitiev meets Moon Eui-Jai for the gold medal. The South Korean eliminated Radion Ketani of Slovakia 6-0. Williams and Ketani will contest for the bronze.     In other categories, two Bulgarians, Serafim Barzakov (139 pounds) and Krasimir Kochev (214 pounds) advanced to the finals.     Barzakov defeated Ukraine's Elbrus Tedeev 5-2 and Kochev ousted Hungary's Zoltan Farkas 7-0.     Barzakov will vie for the gold medal against world and Olympic champion Alireza Dabir of Iran. Dabir advanced after defeating Turkey's Mehmet Yozgat 3-0.     Kochev also faces a tough rival in the 214-pound class - Russia's Georgi Gohchelidze. He downed Ukraine's Vadim Tasoev 4-0 in the semifinals.