Greene frustrated after Moscow exit
Dai Greene admitted his frustration after surrendering his world 400 metres title in Moscow on Tuesday night.
The Welshman, whose build-up to the championships has been plagued by injury and illness, bowed out in the semi-finals.
The 27-year-old, who was ill over the weekend to add to the calf tear that hampered his training over the past weeks, was clearly lacking fitness as he finished fifth in 49.25 seconds.
"The intensity levels were just so difficult to get up," he said.
"That's what I've been missing in the last few weeks and it showed out there.
"I felt I did a good job of keeping the pace that I did have throughout the duration of the race, but when you're racing the top guys in the world and they're not making mistakes you can't be found wanting at all."
It caps a second season of disappointment for Greene, who finished fourth at London 2012 after having knee surgery the previous winter.
And today's emotions were a far cry from those he experienced when he won the world crown in Daegu two years ago.
"It's really frustrating," he said. "But after the last few weeks it's not something I've really thought about.
"You understand you're not in great shape coming into the championships so it does cross your mind that maybe you're not going to make the start line, that maybe you won't be able to be at your best.
"Mentally, I suppose I've considered that once or twice. You prepare yourself for that.
"If I had run a race here and it had been a disaster I would have come off distraught, but as it was, I thought I ran really, really well considering how my body felt. It's not so much of a shock to me, it's just frustration."
Greene's team-mates fared no better. European champion Rhys Williams also went out, finishing fourth in his semi in 49.29secs, and so too did Sebastian Rodger, who finished sixth in 49.32s.