Hisashi Iwakuma pitched seven innings of one-run ball to earn his 20th win of the season, leading the Tohoku Rakuten Golden Eagles to a 6-1 victory over the Seibu Lions on Monday.
Seibu's magic number to win the Pacific League title remained at two, but the Lions can clinch it Tuesday with a win over Rakuten coupled with a loss by the second-place Orix Buffaloes to the Chiba Lotte Marines.
Iwakuma (20-3) won his eighth consecutive decision after allowing six hits, walking none and striking out four.