Takanohana suffered a setback in his comeback from injury as the yokozuna went down to his second defeat against a rank-and-filer at the Autumn Grand Sumo Tournament on Thursday.
Takanohana lost to Kotoryu in the day's penultimate bout at Tokyo's Ryogoku Kokugikan to fall two wins behind early leader Asashoryu, who remained unbeaten with a win over Tosanoumi.
Takanohana (3-2) had withdrawn from a record seven consecutive tourneys after securing his 22nd Emperor's Cup in May last year as he bids to recover from a career-threatening knee injury, but he looked a shadow of his former dominating self against Kotoryu (1-4).
The No. 3 maegashira, who headed into the bout without a victory at the meet, went on the offensive immediately at the charge and pushed the yokozuna to the straw bales before slapping him down in the dirt.
Newly promoted ozeki Asashoryu kept up his spotless record by downing sekiwake Tosanoumi (3-2) to move into the sole lead, but had to get out of jail for a second straight day.
Tosanoumi gained the upper hand from the face-off and looked to be heading for victory as he headed the Mongolian toward the edge of the ring, only to be felled by an underarm throw on the ropes.
Meanwhile, grand champion Musashimaru (4-1) powered his way out of a tight spot in his bout against komusubi Takamisakari (0-5) to head a list of 10 wrestlers one off the lead.
Joining the log-jam of fighters at 4-1 were ozeki trio Kaio, Chiyotaikai and Musoyama.
Kaio, needing eight victories to remain at sumo's second-highest rank, moved halfway to the mark after steamrollering over top-ranked maegashira Tochinonada (0-5).