ATHLETICS: After having her aura of invincibility sorely tested during a string of recent defeats, Sally Pearson is feeling like her old self again.

Which is very good news for the Pearson-led Australian team at the world athletics championships starting in Moscow on Saturday.

And extremely bad news for the powerhouse four-pronged American lineup hoping to end the reigning world and Olympic champion's dominance of the 100m hurdles.

Two hamstring injuries meant Pearson wasn't able to start her 2013 racing program until June.

The first five of her meets produced several uncharacteristic losses and some pretty mediocre times.

But a July 26 return to the London Olympic stadium - the venue of her unforgettable 2012 Games triumph - produced a welcome change in fortune.

The time of 12.65 seconds was still nothing special by her lofty standards, but it was still vitally important to claim the win, sending a clear message to her rivals in the process.

"Hopefully I put that into their minds and reminded them who I am and that I am a competitor when I go into a major championships," said Pearson.

"I think I have just as big a chance as everyone out there and I just can't wait to see what I can produce because everyone knows I am a big-time performer and that is what I thrive on."

Pearson, 26, drew further confidence from a chat with American 110m hurdler Aries Merritt in the wake of her most disappointing run of the year, when she trailed home in fifth spot in 12.75 at the Monaco Diamond League meet.

Like the Australian, Merritt was also hampered by injury after winning the London Olympic title.

"He just said that he believed in me," said Pearson.

"He has obviously been through the same thing I have, except he has done his hamstring three times.

"He said just start believing in yourself now and make sure that you get to those world championships in the best state possible and that sometimes mental strength is far more beneficial than physical strength."

Pearson's long-time coach Sharon Hannan saw clear improvement in her star charge during the London Diamond League win, with those gains consolidated during the recent Australian team camp in the English town of Tonbridge, where the final touches were also put on her 2012 Olympic campaign.

"I am really happy with how she is coming along now," said Hannan.

"I have been seeing some good stuff over a few weeks.

"It still felt a bit messy to Sal because putting that sort of speed over hurdles has always been a challenge but I told her to back herself and know that I knew she was on target."

The formidable US challenge in Moscow will be led by rising star Brianna Rollins, who moved above Pearson to equal third on the all-time list with her blistering time of 12.26 seconds at the US trials in June.

Rollins has deliberately avoided racing against Pearson in the intervening couple of months - a tactic questioned by Australian head coach Eric Hollingsworth.

The other American big gun is Dawn Harper, who won Olympic gold ahead of Pearson in 2008, only for the Australian to reverse the result four years later in London.

The remaining two US representatives, Queen Harrison and Nia Ali, sit second and third on the 2013 rankings.

Pearson is back in equal 10th - for now.

But - with self-belief restored and another major title on the line - almost certainly not for much longer.

John Salvado
AAP