Jason Gardener bowed out in the second round of the 100 metres and then admitted that the back injury which plagued his preparations for the Commonwealth Games had almost prevented him taking part.

The 'Bath Bullet', captain of England's men's athletics team, turned down the chance to defend his world indoor 60 metre crown to compete in Melbourne but was clearly hampered by a back problem.

"I'm just pleased to have got to the start line," said Gardener, who won his opening heat in 10.41 seconds and got a flying start in the second, only to lose momentum in the middle of the race and trail home in fifth place.

"I ran at 80 per cent in the first heat but in the second round the other guys were just too good.

"Because of the problem with my back, I've now also got a hamstring pull and I couldn't really give it everything. Every time I pushed hard, I could feel the ham-string tighten.

"That means I can't play a part in the relay and I now need to return home to get some treatment. The medical team here are under pressure and their priority is to treat athletes who are still competing, so it's best if I go home."

Gardener's England teammates, Birchfield Harrier Mark Lewis-Francis and Coventry's Marlon Devonish, qualified alongside world record holder Asafa Powell of Jamaica for the 100m semi-finals but Wales' Christian Malcolm faces an anxious wait to discover the extent of the hamstring injury which forced him to pull up in his heat.

The 26-year-old is a medal prospect in the 200m but managed only a few metres of his race before limping to a halt.

Coach Phil Manning said: "He felt a twinge in his ham-string. If it's anything more than a twinge, we'll have to leave a decision on the 200 to the medics."

The highlight of the day was the amazing finish to the women's marathon, as Australia's Kerryn McCann delighted the crowd by successfully defending her title.

McCann eventually held off Kenya's Hellen Cherono Koskei by just two seconds in a sprint finish in the stadium after the lead changed hands numerous times in the final kilometre.

Liz Yelling, training partner of Paula Radcliffe, took the bronze in two hours 32 minutes 18 seconds, less than 90 seconds behind the winner. Wales' Tracey Morris recorded a personal best in fourth place, just weeks after resuming training following an Achilles injury.

"It's awesome," said Yelling, who was fourth in the 10,000m in Manchester four years ago. "I've dreamt of it since Manchester last time.

"When I watched Kelly Holmes getting her medal on the podium at the Olympic Games I thought 'I want to do a medal ceremony'. I knew this would be a good opportunity, I'm just overwhelmed to have done it.

"I got a text message from Paula this morning saying 'good luck' but she's in America so the time difference is quite difficult."

In the men's event, Dan Robinson ran a well-judged race to finish behind Tanzania's Samson Ramadhani Nyonyi and Kenya's Fred Mogaka Tumbo and claim a second marathon bronze for England.

The 31-year-old part-time teacher from Cheltenham, who finished 12th in the world championships in Helsinki last year, sensibly decided not to go with the fast early pace and steadily made his way through the field to record a time of 2:14.50, less than a minute outside his personal best.

"I'm so pleased," Robinson said. "I knew I was in good shape to set a good time on this course but, like all championships, you never know. There might be five or six guys in great shape and you can't compete with that.

"I thought it was possible to get a medal. It's just an amazing experience, a great day."

Goldie Sayers' best effort of 57.29m in the final round of the javelin left her clutching her head in her hands as she missed out on a medal. Her personal and season's best of 61.45 would have won the gold, which went to South African Sunette Viljoen.

"I warmed up fantastically well but that first throw really needed to be nailed," said Sayers, who managed only 50.96 with her opening attempt. "I was playing catch-up all the way through the event after that.

"I bruised my heel a couple of days ago;, it's not bad enough to use as an excuse but I didn't feel I was putting my foot firmly into the floor. I'm bitterly disappointed."

In the women's 400m, Christine Ohuruogu, Kimberly Wall and Catherine Murphy all advanced to the next round and, in an essentially pointless exercise, the English trio of Carl Myerscough, Scott Rider and Mark Proctor all qualified for the shot final.

Just 15 athletes were competing for 12 places in the final and 43-year-old Proctor qualified despite a best of just 15.91m.