Sally Pearson has been trumped by her principal rival for Commonwealth Games gold in her final race before her title defence in Glasgow.

Olympic champion Pearson finished third in a competitive time of 12.79 seconds in the 100m hurdles at the Anniversary Games in London on Sunday (Monday AEST), easily her best time since suffering a hamstring injury in June which has hindered her Games preparations.

But she will be concerned at being beaten to the finish line by England’s Tiffany Porter, who produced a late burst of speed to win in 12.71.

In windy conditions at a temporary stadium at Horse Guards Parade in central London, Pearson perhaps gave a hint that she is still not quite 100 per cent and is carrying more nerves than usual when she jumped early, prompting a false start.

But rather than be disqualified, the 27-year-old and the rest of the field were shown a green warning card.

Despite that setback, Pearson managed to get the jump on her competition and looked in control at the halfway mark, before Porter took over.

The 26-year-old hit the afterburners to pull away over the final 30 metres, as Pearson was also overtaken by Brianna Rollins of the United States.

Pearson has gradually worked her way back from a hamstring complaint suffered in Rome in early June.

After a sluggish time of 13.19 in Belgium just under a month ago, Pearson has consistently posted times in the region of 12.9 – still well short of her season best of 12.59 and a long way off her personal best 12.28.

Meanwhile, Alana Boyd warmed up for her Commonwealth pole vault gold medal defence with another strong performance – clearing 4.55m to claim second.

Boyd is the runaway favourite to secure gold, with the achievements of her rivals dwarfed by the 30-year-old Victorian’s impressive jumps this year in a sport that is primarily dominated by American and European athletes.

Earlier, 1500 metre runner Zoe Buckman was a strong third in the women’s one-mile race, edging out countrywoman Genevieve Lacaze by one second in a time of 4:43, while Collis Birmingham finished ninth in the men’s two-mile race in a time of 8:43.