SOFIA, Bulgaria (AP) - Bulvaisa Saitiev of Russia captured his fourth world championship with a 3-1 victory over Korea's Eui-Jae Moon in the 168-pound weight class at the wrestling world championships on Saturday.     Saitiev, who narrowly defeated Joe Williams of the United States in the semifinals, also has two Olympic and five European championship titles. Williams lost 5-4 after the judges ruled he had stepped outside the mat on a spectacular thow that brought down Saitiev.     Another Russian, Georgi Gogchelidze, successfully defended his title in the 214-pound class, winning 3-0 against Bulgaria's Krassimir Kochev. Gogchelidze was a silver medalist at this year's European Championship.     Bulgaria's Serafim Barzakov took the men's 139-pound title with a last-minute victory over world and Olympic champion Alireza Dabir of Iran. After a 1-1 tie in regular time, Barzakov, a silver medalist at the 2000 Olympics, scored two technical points from a clinch and seal the victory.     Belarus's Herman Kantoev took the gold medal in the men's 119-pound category, with a 4-1 win over Iranian Babak Nurzak.     Three titles were also awarded in the women's competition.     Defending world champion Christine Nordhagen of Canada defeated American Toccara Montgomery 4-1 to win the gold medal of the 150-pound class.     Earlier, Montgomery won her fourth straight match, pinning Russia's Sveta Yaroshevich in 3 minutes, 12 seconds to advance to the finals. Nordhagen had defeated Germany's Anita Schatzle 10-4 in her semifinal.     Ukraine's Irina Melnik defended her title in the 101-pound final when she beat Canada's Carol Huynh 3-0.     Japan's Seiko Yamamoto also reclaimed her championship title in the 123-pound class in a tough, 7:40 minute battle against newcomer Liubov Volosova of Russia. Yamamoto and Volosova were tied 1-1 after more than seven minutes, when Yamamoto scored a decisive 3-point takedown.     Yamamotu had pinned Lee Na Lae of South Korea for a 6-0 victory in the semifinals while Volosova ousted Tatyana Lazareva of Ukraine 4-2. Lazareva won a silver medal at the 2000 world championships.