Christine Ohuruogu is planning to maintain her unbeaten record in the 400 metres this season in tonight's star-studded Aviva London Grand Prix at Crystal Palace.

The reigning world champion's clash with Nicola Sanders, who she beat for the gold medal by half a stride in Osaka last August, will be their first clash this term.

Indeed, given Tyson Gay's late withdrawal from the meeting, it is likely to overshadow a 100 metres which had been billed as the world champion's eagerly anticipated head-to-head with former world record holder Asafa Powell.

Ohuruogu and Sanders, for different reasons, have raced sparingly over 400metres this summer, the latter nursing hamstring and knee problems which have reduced her to just two races at the distance this season.

But her win in last last month's European Cup showed her class - a statement she reinforced with an excellent victory in Milan when clocking 50.88seconds.

Ohuruogu has three wins out of three and in her last outing in Lucerne was just one hundredth of a second slower than Sanders.

The pair, along with Lee McConnell, could also be in with a chance of relay glory in Beijing and will be aiming to show their form before heading off to the Olympics.

Ohuruogu, playing down the clash with Sanders so soon before leaving for China, said: "It is no big issue. Whoever turns up, turns up. I am just there to compete and put a good race in before I leave.

"I have no issues racing against anyone."

Sanders, who is using the event as a fitness check, said: "I'm looking forward to seeing what sort of shape I'm in, which is something Crystal Palace will tell me."

Other Beijing-bound stars in action include British 100m pair Tyrone Edgar and Craig Pickering.

Fellow sprinter Powell is coming to the Palace not quite in mint condition but still in world-class form after defeating world record holder Usain Bolt with a season's best time of 9.84secs in Stockholm on Tuesday.

Powell said: "I got very nervous with the shoulder injury and I thought to myself, 'My Olympic Games is over'.

"Now I'm still running around 9.88 seconds, so I'm content.

The Commonwealth champion believes he made mistakes despite his success in Stockholm and claims he could have gone even quicker.

He added: "I forgot what it takes to run a fast race - I was trying too hard and I do better when I don't try too hard."

Heptathlon gold medal prospect Kelly Sotherton will contest a four-event schedule, while Phillips Idowu is another strong tip for victory in the triple jump.

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