Yokohama could have wrapped up the title on Saturday but they fell to a 2-0 defeat to Albirex Niigata, a result that saw their lead at the top cut to two points.
The league leaders dominated possession and had more shots than their opponents but were ultimately unable to convert.
Sanfrecce's 1-0 win over already relegated Shonan Bellmare means the defending champions are within striking distance of the title going into their final match of the season.
Toshihiro Aoyama's 36th-minute strike – his third of the season – was enough to seal the victory for Hajime Moriyasu's side.
Kashima Antlers slim hopes of lifting the trophy remain alive after their 2-1 win over Cerezo Osaka, but they needed a late winner from Atsuka Nakamura to secure all three points after Yoichiro Kakitani had cancelled out Yuya Osaka's 25th-minute opener.
Urawa Reds saw their title hopes ended as they fell to a second consecutive defeat – which extends their winless run to three matches.
Like Shonan, the other two already-relegated sides – Oita Trinita and Jubilo Iwata – fell to defeat.
Elsewhere, Shimizu S-Pulse recorded back-to-back wins with a 2-1 victory over Vegalta Sendai, Kashiwa Reysol ended a run of three games without a win as they beat Tokyo 4-1 and Nagoya Grampus battled out a goalless draw with Ventforet Kofu.
