Martyn Rooney and Lawrence Okoye will go into this weekend’s Diamond League encounter at Crystal Palace sweating over their places at the World Championships later this month.

Both endured disappointing results at the UK Championships last weekend, which doubled up as the trials for the Worlds in South Korea, which begin on August 27.

Although Rooney won a competitive 400m final, he is not guaranteed a spot on the plane to Daegu as his 45.44 second clocking, a season’s best but short of his personal best of 44.60, was slower than the 45.25 A standard time required, which he will be aiming to run at Crystal Palace.

His fellow Croydon Harrier Okoye does have the A standard in the discus having thrown a UK record 67.73m last month, but he failed to deliver at the trials, coming just fifth with a 58.67m throw.

Adbul Buhari and Carl Myerscough took two of three World Championship spots, and the selectors will have to choose between Okoye and the more consistent Brett Morse for the final place when they announce their squad on August 10.

Ned Quiney, another Croydon Harrier failed to register a jump at the trials in Birmingham.

Sprinter Asafa Powell will be the main attraction at Crystal Palace, with action taking place on Friday and Saturday.

Rooney's 400m race takes place at 8.27pm tomorrow night, while Okoye will be in the discus from 1.15pm on Saturday.