Black, a 400m silver medallist behind Michael Johnson at the 1996 Atlanta Olympics, claims the defending women's 400m champion is ready to spring another surprise at London 2012.
Few thought Ohuruogu would win either of her two major titles, at the 2007 World Championships in Osaka and Beijing Olympics one year later.
And despite three disappointing years, Black believes the 27-year old's storming 4x400m gold medal winning third leg at the recent World Indoor Championship was a major indication of intent.
“She is the one that people are not talking enough about," said Black, after joining over 5,000 runners in the National Lottery's Olympic Park Run, the first competitive action at the new £500m stadium.
"Don’t write her off. People talk about Jessica Ennis, they talk about Dai Greene and they talk about Mo Farah. Phillips Idowu gets the attention as well but no-one mentions Christine and they should.
“People always ask me ‘what’s your outside bet for the Olympics?’ and I say ‘never write off a champion.’
"If she is healthy, and apparently she is, it all becomes easy again. She is a phenomenal competitor and she knows how to win races – better than anyone else. She has got it.
“Don’t be surprised if she turns up here for the Olympic Games and causes quite a stir. I rate her and I've always have rated her. She knows how to run races and that’s all you need to do in the Olympic final.
"She has been injured and if you are injured it doesn’t matter who you are – in the 400m, you are in trouble."
But Black believes 400m hurdler Greene - too often the forgotten man of British athletics - remains Team GB's best chance of winning Olympic gold.
Greene won the world title in Daegu last year but didn't even make the top three in the Welsh sports personality awards - beaten by motorcyclist Chaz Davies, triathlete Helen Jenkins and Paralympic javelin thrower Nathan Stephens.
But should he win in London he will join an exclusive few to have held the World, European, Commonwealth and Olympic titles at the same time.
“He is a great competitor. It is not about the times – it is about the best," added Black.
"When you race Dai Greene, you know you have to race him. He is the world champion and is a hard man to beat.
“He will be thinking gold medal. He won’t be thinking anything else other than that. And why shouldn’t he? He is the world champion. Why would he think anything less than that?
“He is one of five athletes that could win gold medals. I think Dai is our best chance. The other three are Jessica [Ennis], Phillips [Idowu], Mo [Farah], and then Christine."