Reigning Olympic 500 metre champion Anna Meares saved Australia's blushes at the Laoshan velodrome here Tuesday when she qualified in dramatic fashion for the final of the women's sprint.
Her feat means Australia - who have yet to win a medal from the seven finals so far - were guaranteed either silver or gold, and will avoid equalling an unwanted national record.
The last time Australia went home without a track cycling medal from the Games was at Moscow in 1980.
After losing to a dominant Guo in the first leg of their semi, Meares' fought back in the second taking the lead and holding off the resurgent Chinese star at the line.
It went to a third leg decider, which the jury allowed to be re-run after Guo crashed by herself early in the race as she manoeuvred awkwardly in a bid to move up the boards.
In the re-run Guo led at the bell to signal the final lap, but as the pair came round the bend leading to the finish Guo clashed with Meares, who had to steady herself to avoid coming down.
Guo went on to pip Meares at the finish, prompting massive celebrations among the Chinese fans.
The Australian reponded by pumping her first in a victory salute. It was a premature celebration that, moments later, turned out to be justified when Guo was disqualified.
The Aussies were the kings of the velodrome in 2004, but since then have been playing catch-up to the dominant British team.
Australia finished just off the podium several times during the five-day competition, in which Britain have so far won five gold, for a total of nine medals.
To rub salt into the wounds, Britain are set to win more gold on the final day.
They have two riders, Chris Hoy and Jason Kenny, in the gold medal match for the men's sprint gold, while Meares will meet Britain’s Victoria Pendleton in their gold medal match.
Bradley Wiggins and Mark Cavendish of Britain also started the men’s Madison as the world champions and gold medal favourites.
Meares' feat in making the Olympic final comes only seven months after she returned home from a World Cup race in a wheelchair following a crash which almost left her permanently paralysed.
As well as winning sprint bronze in Athens, she is also the champion in the now defunct Olympic event of the 500 metre time trial.