Bulgaria's Grigor Dimitrov won his first title in over two years when he upset world No. 5 Kei Nishikori in three sets to win the Brisbane International Tennis Tournament Sunday. In an enthralling final between two evenly matched opponents, Dimitrov claimed the Roy Emerson Trophy 6-2, 2-6, 6-3, his fourth singles title on the ATP Tour. Dimitrov was ranked as high as eighth in the world in 2014 and was nicknamed "Baby Fed" because of his similar playing style to Swiss great Roger Federer. Injury problems and poor form saw him slump during 2015 and the first half of 2016, when he plummeted to 40th in the world. But he recovered toward the end of last year and entered the season-opening tournament ranked 17. The Brisbane win will see him climb to 15 when the rankings are released Monday. Dimitrov insisted he had not felt under pressure because of his rankings slide and said he knew he would eventually get the rewards for the hard work he was doing off court. "I think that was kind of an emotional win for me, but at the same time, it wasn't unexpected," he said. "I think I have put in the work. I think I have learnt a lot. I have set myself quite high goals for the first six months, and one of them was actually to win a tournament," he added. "And it happened during the first week of the year." Despite Dimitrov's win over top seed Milos Raonic in the semifinals, the 27-year-old Nishikori had not lost to the Bulgarian in three previous meetings and went into the final as firm favorite. Bouchard wins 1st-round match Eugenie Bouchard made the most of her wild-card entry to the Sydney International, beating Zhang Shuai of China 7-6 (1), 6-2 on Sunday in a first-round match. Bouchard, a 22-year-old former Wimbledon finalist, was beaten in the first round of the Brisbane International last week in her first warm-up tournament for the Australian Open, which begins on Jan. 16 and where she was a surprise semifinalist in 2014. Earlier at Sydney, two-time Grand Slam singles champion Svetlana Kuznetsova defeated Irina-Camelia Begu of Romania 6-1, 6-4. Earlier, Brisbane International finalists Karolina Pliskova and Alize Cornet withdrew from their next scheduled tournaments due to injuries. Pliskova, who would have been seeded fourth in Sydney, was replaced by lucky loser Roberta Vinci of Italy. Sydney officials also announced seventh-seed Elina Svitolina of Ukraine withdrew due to a viral illness. No. 1 Angelique Kerber and third-ranked Agnieszka Radwanska remain in the Sydney draw. American Shelby Rogers posted the first upset of that tournament in the opening match, beating second-seeded Anastasija Sevastova of Latvia 6-2, 1-6, 6-4. Lizette Cabrera of Australia continued the Hobart trend, beating fifth-seeded Misaki Doi of Japan 6-4, 5-7, 7-5. — Agencies