(Reuters) - Taylor Fritz beat fellow American Frances Tiafoe 7-6(3) 7-6(2) in a tense final to win the Japan Open on Sunday and claim his third title of the year.The two 24-year-olds traded breaks in the opening set before the greater consistency of Fritz took him ahead in the tiebreak and he secured it with a cracking forehand.The second set was equally intense as Fritz's serve proved impenetrable and Tiafoe bravely defended several break point chances inside Tokyo's Ariake Coliseum.In the tiebreak, Fritz raced into a 6-2 lead with relentless power and accuracy before sealing victory when Tiafoe's forehand went out.Fritz, assured of breaking into the top 10 after beating Canada's Denis Shapovalov in the semi-finals, also won titles in Eastbourne and Indian this year.