Khamis began his 2014 season with a 400 m sprint/hurdles double at the Arab Junior Athletics Championships in Cairo. He made his debut on the IAAF Diamond League circuit in May, running in the 400 m at the Doha Diamond League and placing runner-up. The hurdles remained his focus that year, as he returned in the event at the 2014 World Junior Championships in Athletics. He set a string of bests at the competition, improving from 51.10 in the heats to 49.55 seconds in the final – a time which brought him second place to Jamaica's Jaheel Hyde. 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. He ranked in the top fifty worldwide and second in Asia on time that season, behind only Kazakhstan's Dmitriy Koblov.