Rugby: US Sevens star Carlin Isles bombs certain try at Cape Town Sevens

Carlin Isles of the USA. Photo / Getty Images.

USA Sevens speedster Carlin Isles bombed a certain try during his side's 26-5 victory over Spain at the Cape Town Sevens in South Africa overnight (NZT).

The American star - who shot to fame five years ago when a highlights reel of him running around defenders with ease went viral - used his blistering pace to weave through the helpless Spanish defenders from deep inside his own half.

However, in what can only be described as a massive brain explosion, the 28-year-old dropped the ball cold 40 metres from the tryline with no opposition players in sight.

The former track and field athlete displayed a wry smile before regathering the ball and throwing it into the air in frustration.

Fortunately for him, his error did not harm the USA's chances at the tournament, as they went undefeated through pool play, including a 22-0 win over the All Blacks Sevens.

They will face Argentina in their Cup quarter-final on day two of the tournament tonight (NZT).