TOKYO (Kyodo) -- Former ozeki Shodai sprang a major upset Sunday by handing yokozuna aspirant Hoshoryu his second loss of the New Year Grand Sumo Tournament.

The unexpected result leaves the Mongolian ozeki two wins off the pace at 6-2 and hampers his bid to reach sumo's top rank following the mid-tournament retirement of Terunofuji, which has left the sport without an active grand champion.

Hoshoryu earned a shot at promotion by finishing runner-up with a 13-2 record in November and must produce another championship-caliber performance at the ongoing 15-day tournament at Tokyo's Ryogoku Kokugikan arena.

Fighting as a No. 4 maegashira, Shodai (3-5) turned back the clock in the final bout of Day 8, standing his ground in the face of Hoshoryu's strong initial charge before rallying for a frontal push down victory.

"It was the last bout of the day, and I wanted to display strong sumo," Shodai said. "Things haven't been working too well, and I needed to turn things around, but today, I was able to move forward."

Kinbozan, the No. 14 maegashira from Kazakhstan, finished the day as outright leader and the first wrestler with a winning record for the tournament at 8-0 after forcing out No. 10 maegashira Tamawashi (6-2).

No. 5 maegashira Chiyoshoma and No. 11 maegashira Takerufuji share the second rung of the leaderboard at 7-1.

A day after snapping a five-loss streak, ozeki Kotozakura (3-5) continued to right the ship by throwing out No. 3 maegashira Oho (6-2), who started with six straight wins before losing back-to-back against ozeki opponents. Ozeki Onosato improved to 5-3 by forcing out komusubi Wakatakakage (3-5).