Usain Bolt sent an ominous warning by running a season's best time of 9.86 seconds in the 100 metre semi-finals at Rio 2016 on Sunday.

The Jamaican sprint sensation is aiming to become the first man to win three Olympic gold medals in the 100m and appeared the class of the field with a stunning run.

Bolt did not make a great start in the second of three semis, but soon powered ahead and was able to ease up well before the line.

His rival Justin Gatlin has work to do if he is to upset the odds after running a time of 9.94 secs. The American - who has twice been banned for doping - was booed by the crowd during his semi.

Yohan Blake, Bolt's compatriot and silver medallist at London 2012, made it through in Gatlin's semi with a time of 10.01 secs.

Canada's Andre de Grasse ran the second-quickest time in 9.92 secs, while Trayvon Bromell of the United States, South Africa's Akani Simbine, Jimmy Vicaut of France and Ivorian Ben Youssef Meite also qualified for the final.