Koji Chikamoto hit a two-run home run, and Hiroto Saiki threw five effective innings as the Hanshin Tigers avoided a three-game sweep by the Yomiuri Giants with a 4-2 win Sunday. Chikamoto homered to open the scoring in a three-run third inning off Rei Takahashi (2-1) at Tokyo Dome. Saiki (3-1) held Yomiuri to two runs before four relievers each pitched a scoreless inning. The Giants pulled within 3-2 in the fifth, but Ukyo Maegawa singled in an insurance run in the eighth for the Central League-leading Tigers. Among Sunday’s other games, the Pacific League-leading SoftBank Hawks blanked the S…