FUKUOKA (Kyodo) -- Ozeki Kotozakura celebrated his 27th birthday Tuesday at the Kyushu Grand Sumo Tournament with a victory over rank-and-file opponent Tobizaru that kept the joint overnight leader on top of the standings.

Kotozakura continued to share the top rung with fellow ozeki Hoshoryu and No. 6 maegashira Takanosho at 9-1, but new ozeki Onosato dropped further off the pace with an unexpected loss to sekiwake Daieisho that left him at 7-3 on Day 10 at Fukuoka Kokusai Center.

Having secured a belt hold at the jump, No. 5 maegashira Tobizaru (6-4) had little chance to use it before being yanked to the sandy surface by the firmly planted Kotozakura, who is gunning for his maiden Emperor's Cup.

Daieisho (6-4) pulled off the day's biggest upset with an uncharacteristic force out after being driven to the edge by May and September champion Onosato, one of the pre-tournament favorites in the absence of injured yokozuna Terunofuji.

"He's got a big body and I tried to keep him off me," said Daieisho, who needs two more wins to guarantee his place among the three "sanyaku" ranks below yokozuna. "A winning record is my aim every tournament, so that's what I'm mainly thinking about."

Hoshoryu consigned Kotoshoho to a losing record at 2-8 after pinning the No. 5 maegashira's arm and marshalling him over the straw bales.

Former sekiwake Takanosho slapped down No. 15 maegashira Onokatsu (7-3), knocking him from the main chasing pack. The joint leader will face his sternest test of the tournament thus far against Onosato on Day 11.

Another former sekiwake, third-ranked maegashira Abi, shares the second rung with No. 16 maegashira Takerufuji at 8-2 after tossing No. 1 maegashira Hiradoumi (1-9) and snapping a four-match losing streak in their head-to-head rivalry.

Takerufuji (8-2) clinched a winning record in his first makuuchi division tournament since winning the Emperor's Cup in March as a top-flight debutant. The Isegahama stable wrestler, who worked his way back from an ankle injury after the historic championship, pushed down former sekiwake Meisei (6-4), now a No. 11 maegashira.