Dina Asher-Smith rival, Blessing Okagbare, provisionally suspended for use of human growth hormone

The Olympics suffered its first major doping case on Saturday morning when Nigerian sprinter Blessing Okagbare - a big contender for 100 metres and 200m medals - was provisionally suspended for using a human growth hormone, 12 hours after starting her podium quest in Tokyo.

Okagbare, 32, won her 100m heat with ease on Friday night and was due to line up in the same semi-final as Dina Asher-Smith on Saturday evening. She will now take no further part in the Olympics.

The drugs sample was collected from Okagbare in an out-of-competition test on July 19, but the laboratory that analysed it only informed the Athletics Integrity Unit of the positive result after Okagbare’s first-round triumph on Friday. She was told about it on Saturday morning.

A regular in global sprint finals, Okagbare ran the second-fastest 100m time in all conditions last month when clocking 10.63 seconds in Lagos. The time did not count as legal due to the 2.7m/s tailwind.

Okagbare’s ban is the latest doping shock to hit the Nigerian team after 10 of its 23 track and field athletes were struck off the startlists on the eve of competition when they were told they had not taken enough drugs tests to be eligible to compete.

Nigeria is one of seven ‘Category A’ countries deemed most at risk of doping and therefore subject to stricter controls than other nations. All Nigerian athletes must undergo at least three no-notice, out-of-competition tests in the 10 months leading to a major event. Only then are they eligible to compete at the Olympics.

As well as Nigeria’s 10 athletes, three were struck off from Ukraine and Belarus, one from Morocco and one from Ethiopia. Two Kenyan athletes were also deemed not to be eligible, but Athletics Kenya had already replaced them before submitting its final entries earlier this month.

All 13 athletes from Bahrain, which is also a ‘Category A’ country, were cleared to compete.

Okagbare’s absence continues a raft of high-profile track and field athletes to miss these Tokyo Games. World 100m champion Christian Coleman and world 400m champion Salwa Eid Naser are banned after doping test whereabouts failures, while fellow American sprinter Sha’Carri Richardson is also absent after testing positive for cannabis.