Asashoryu came from behind to beat Dejima at the Autumn Grand Sumo Tournament on Tuesday, throwing the No. 5 maegashira to the dirt surface after narrowly avoiding defeat.
The yokozuna's victory transformed the tournament into a tight battle between four wrestlers with 8-2 records.
The Mongolian champion, who is aiming to win his fifth straight Emperor's Cup, has had a rocky tournament so far. He lost to two lower ranked wrestlers on the fourth and fifth days.
The yokozuna almost fell on his hands Tuesday after Dejima grabbed his right side, but Asashoryu fought back to push him to the edge and throw him to the dirt surface.
Dejima's record dropped to 8-2 with five days left in the 15-day tournament at Tokyo's Ryogoku Kokugikan.
Ozeki Kaio overcame Tosanoumi, despite repeated lunges from the No. 4 maegashira wrestler at Kaio's neck. Kaio sent Tosanoumi flying off the mound and into the front row of the audience with a hard push to the junior wrestler's chest. Kaio improved to 8-2.
Kyokushuzan lost his second match in as many days as No. 16 maegashira Takanotsuru pushed the Mongolian wrestler out of the raised ring with the full thrust of his arms and his stomach.
The Ulan Bator native, who had been the tourney's sole undefeated grappler until Dejima edged him out of the ring on Monday, fell to 8-2.
Wakanosato slid to 7-3 after Miyabima beat him with multiple hard blows to the neck. Wakanosato had the upper hand at several points during the match against his fellow sekiwake, only to lose ground when Miyabima attacked him with a persistent series of arm thrusts.
Hakuho defeated Iwakiyama by grabbing hold of the No. 2 maegashira by the belt, turning him around full circle and sending him sailing off the raised ring.