BEIJING -- Much-hyped world champion Teddy Riner saw his Olympic gold medal hopes end at the quarterfinal stage of the men's +100-kilogram judo competition at the Beijing Olympics on Friday.

That defeat ended all hopes of a dream final against rising Japanese star Satoshi Ishii, who qualified for the semi-finals in impressive fashion.

Ishii unleashed his full repertoire of throws in the first two rounds, downing Italy's Paolo Biachessi with uchi-mata (inner thigh throw) and then Egypt's Islam El Shehaby with ouchi-gari (major inner reap).

In the last eight he came up against dangerous Russian Tamerlan Tmenov, the silver medalist from Athens, but prevailed by virtue of his strong ground fighting.

Tmenov dithered on the floor after a failed attack and was caught by Ishii who secured a hold, only for the Russian to submit when he knew he was beaten.

Frenchman Riner had started slowly on the opposite side of the draw, needing a minute of over-time golden score to beat Anis Chedly of Tunisia.

The 19-year-old has been the talk of the judo world after a dream 2007 where he lifted both the European and world crowns.

He seemed to have found his form in the next round, dismissing Kazakh Yeldos Ikhsangaliyev in just 50 seconds with osoto-gari (major outer reap).

But he simply could not find a way to defeat Uzbek Abdullo Tangriev in the quarterfinals, eventually falling in the last minute of golden score when he was penalized for negativity.

Ishii will face Georgia's Lasha Gujejiani in the evening semi-finals while Tangriev comes up against Oscar Brayson of Cuba.

In the women's +78kg division double world champion Tong Wen of China and reigning champion Maki Tsukada of Japan remained on course to meet in the final.

Tong beat Tsukada in the World Championships final last year but wasn't selected for the last Olympics when the Japanese took the title.

Tong made short work of her first opponent Tea Donguzashvili of Russia, throwing her for ippon with a harai-makikomi (sweeping winding throw).

She then used her incredible strength to flip her next two opponents over onto their backs on the ground to pin them.

Tong tossed two 120kg women over as if they were pancakes in a frying pan and will meet Cuba's Idalys Ortiz in the semi-final.

Tsukada defeated three-time reigning European champion Anne-Sophie Mondiere of France in her first fight and then saw her path to the last four opened up by a shock defeat for Britain's Karina Bryant.

The Japanese then pinned Mexico's Vanessa Zambotti and will square up to Lucija Polavder of Slovenia in the last four.