Argentina's Paula Pareto and Russia's Beslan Mudranov grabbed the gold medals on day one of the Rio 2016 Olympic Games judo competition, but there was heartache for home favourite Sarah Menezes as she ended up in hospital rather than on the podium.

In the women's -48kg, Pareto became the first Argentine judoka to win an Olympic Games gold. The 2015 world champion dominated Republic of Korea's Jeong Bokyeong in the final and won by waza-ari.

The bronze medals went to Japan's Ami Kondo and Otgontsetseg Galbadrakh of Kazakhstan.

London 2012 Olympic champion Menezes came into the Games as a huge medal hope for Brazil but lost in the quarter-final against Cuba's Dayaris Mestre Alvarez and then in the repechage to Mongolia's Urantsetseg Munkhbat, suffering a dislocated ellbow in the bout.

Top seed Munkhbat was disqualified for leg grabbing in the quarter-final against Jeong.

Mudranov defeated Kazakhstan's 2015 world champion Yeldos Smetow by golden score in the extra time in the men's -60kg final.

There was no score in the regular match time of five minutes, but then Mudranov threw Smetov to achieve waza-ari.

Japan's Naohisa Takato and Diyorbek Urozboev of Uzbekistan earned the bronze medals.

The biggest upset came when Mudranov beat Republic of Korea's world No.1 Kim Won Jin in the quarter-final.

In the women's -52kg on Sunday, former world champion Majlinda Kelmendi could win the first Olympic medal for Kosovo, which is represented for the first time in Olympic Games. World silver medallist Andreea Chitu, of Romania, is the top seed.