Ayumu Ishikawa tossed six shutout innings as the Pacific League-leading Chiba Lotte Marines claimed a 1-0 win over the Hokkaido Nippon Ham Fighters on Monday, moving 3½ games clear of the Orix Buffaloes.
Ishikawa (3-2), who returned this month after having surgery on his right elbow in June, struck out three without issuing a walk in a 92-pitch effort at Sapporo Dome.
Takuma Kato scored the only run in the sixth, opening the inning with a double off Nippon Ham lefty Ryusei Kawano (2-4) and coming home on a one-out sacrifice fly by Kyota Fujiwara.