Accompanied by a noise which could have launched a moon rocket Kerryn McCann at last gave the 2006 Commonwealth Games a performance on which to build its credibility.

From now on whenever the gutsiest duels in sport are debated McCann's victory over Kenya's Hellen Cherono Koskei in an epic women's marathon will deserve to be included.

Partly because here was a 38-year-old mum of two who had defied advancing years and the demands of her growing family to defend the gold medal she won in Manchester four years ago.

Partly because McCann defied cramp and the demons in her own mind to reward the huge crowds who had turned out to watch the first day of athletics here.

But mostly because the race epitomised what tough, courageous sporting combat is all about.

Yes, we should not forget that England's Liz Yelling won the bronze medal with the bravest of runs to hang on when the leading pair had broken free.

Yet it is McCann and Koskei on whom history will focus even though the winning time of two hours 30 minutes and 54 seconds would have allowed world record holder Paula Radcliffe to have showered, done her hair and applied her make-up before they came home.

Radcliffe's best is some 15 minutes and 29 seconds better.

But this was not about record breaking. It was about racing and resisting those cynics who say the Games are about cheap, easy medals.

Often that is the case, but not in the Melbourne Cricket Ground on a morning when 80,000 Melburnians packed in ostensibly for a hotch-potch programme of mainly first round heats which promised little.

Instead they witnessed something extraordinary, the lead in a marathon changing hands five times in the last kilometre, the result uncertain until the athletes reached the final bend and McCann delivered one final killing thrust of pace.

"I have never been in a race like that before," said McCann. "I had cramp in my calves and I thought I was gone. I was telling myself that the silver medal was good. I was going and I found something.

"It was the crowd who lifted me. All my pain went away in that last 300m. I have never run 300m faster."

No wonder. The MCG may have experienced a louder roar when Dennis Lillee or Shane Warne took the winning wicket in an Ashes Test, but never one more sustained.

McCann could hear the crowd from a quarter of a mile away. When she entered the stadium her stride noticeably quickened as Koskei's, for the first time, appeared to check.

"It has got to be my greatest victory and the greatest race I have been in," said McCann, who plucked her eight-year-old son Benny out of the crowd to accompany her on an emotional lap of honour.

"I have never been in a situation like that at the end of a marathon. I will cherish it forever."

Son Danny was more concerned that she did not give up yet - she plans one more marathon before possibly retiring at the end of the year - as he wants another trip to Disneyland.

And you had to wonder at the inequity of McCann receiving not a penny for one of sport's most uplifting moments while Radcliffe will rake in £160,000 for simply turning up at the start line for next month's London marathon.

You can't put a price on memories.

Which is why Yelling described her bronze as "awesome" and reward for the hard work she has put in since missing out in Manchester and finishing 25th at the Athens Olympics.

For Welsh girl Tracey Morris, who had not even competed in a marathon until Athens, there was fourth place and a personal best of 2:33.13 after recovering from an ankle operation last summer.

"I've a had a bit of a crash course in running," she quipped. The same might have been said of Aussie Kate Smythe who entered the stadium with her muscles in such a state of oxygen debt that she resembled John Cleese doing his Ministry of Silly Walks sketch.

Her legs drunkenly stretched in front of her, back arched and head pointed to the sky as she staggered to the line. She crossed it, just, stretching a leg tentatively as if trying to board a rocking boat, and then took two involuntary steps back across the line.

She tried again and still not realising whether she had made it or not, a few seconds later collapsed and was taken away on a stretcher. She finished seventh.

It was the epitome of courage on the day McCann and Koskei and Yelling and co. stirred the Commonwealth Games into vibrant life.