[1] At the 2012 Asian Junior Athletics Championships – despite winning his heat in a best of 52.67 seconds – he faltered in the 400 m hurdles final and finished last.

[2] Two national junior records in the 400 metres sprint came for Khamis at the 2013 Arab Athletics Championships: he ran 46.90 seconds in the qualifiers then 46.25 seconds in the final to take the bronze medal (his first senior podium finish) behind Saudi athletes Yousef Masrahi and Ismail Al-Sabiani.

wtsh Khamis began his 2014 season with a 400 m sprint/hurdles double at the Arab Junior Athletics Championships in Cairo.

[2][6] He maintained this form at the 2014 Asian Games held two months later and a run of 49.71 seconds was enough for the Bahraini teenager to win the 400 m hurdles gold medal.

[7] He ranked in the top fifty worldwide and second in Asia on time that season, behind only Kazakhstan's Dmitriy Koblov.