Hakuho was pushed back to the edge by his fellow ozeki but eventually prevailed when he spun Chiyotaikai around at the center of the ring and shoved him out to improve to a perfect 14-0 in the 15-day Summer Grand Sumo Tournament.

"I'm very happy," said Hakuho. "I had a lot of ups and downs last year so this is very satisfying. I just tried to stay focused on my own sumo."

Chiyotaikai dropped to 10-4.

Hakuho won the Spring tourney in March. The Japan Sumo Association will deliberate on Hakuho's promotion to the sport's highest rank after the conclusion of the Summer tourney but it is widely regarded that two titles in a row are good enough to be promoted.

Sumo hasn't had two grand champions competing at the same time since November of 2003 when Musashimaru retired.

If he is promoted, the 22-year-old Hakuho would become sumo's 69th yokozuna.

In Saturday's final bout, Bulgarian ozeki Kotooshu upset Mongolian Asashoryu, the lone grand champion currently competing in sumo.

Kotooshu, who improved to 9-5, used an arm throw at the center of the ring to send Asashoryu sprawling to the dirt surface.

Asashoryu, who has bidding for his 21st Emperor's Cup, has not been his usual dominant self and dropped to 10-4 after his third straight loss.

In an earlier bout, Mongolian Asasekiryu, a No. 8 maegashira, kept his title hopes alive when he overpowered Russian Roho to improve to 12-2. Ninth-ranked Roho dropped to 9-5.

Sekiwake Kotomitsuki muscled out ozeki Kaio to improve to 11-3. Kaio dropped to 9-5.

No. 10 maegashira Dejima fell out of contention and to an 11-3 record when he was shoved out by giant-killer Aminishiki.

Fourth-ranked Aminishiki, who has beaten Asashoryu and two ozeki in this tourney, improved to 9-5.