Team GB hurdlers Dai Greene (coach: Malcolm Arnold) and Rhys Williams (Dan Pfaff) were left to ponder different circumstances after a testing semi-finals day in the 400m hurdles at the London 2012 Olympic Games.

Dai Greene qualified for the final as a fastest loser after finishing fourth in heat one in 48.19 - a time faster than the one that saw him triumph in the World Championships last year.

However, Rhys Williams's valiant effort in heat three saw him finish fourth in 49.63, possibly a result of the taxing expense of energies required by his strong finish in yesterday's first round.

World Champion Greene was disappointed with his performance despite making the final.

"I just don’t really know what went wrong. I can’t really explain how I feel. I’m just devastated," he said after crossing the line.

"I’m still second fastest qualifier, but that ‘s no way to perform if you are world champ in my mind. I feel like I’ve let everybody down. I should be able to do better than that. I know I’m better than that. It’s really disappointing nonetheless, I shouldn’t be making the final that way."

Williams was understandably dejected:

"I gave it everything. I’m absolutely gutted, gutted that’s as far as I’ve gone, I’m not going to get a chance to go out there. I've got mixed emotions but I gave it everything I just didn’t have the legs at the end of the race."

Tomorrow sees no Welsh athletes involved, while on Monday Gareth Warburton (800m, Darrell Maynard) and Brett Morse (Discus, Vesteinn Hafsteinsson) make their London 2012 debut before Dai Greene is back for the final of the 400m hurdles.