Defending champion Samantha Stosur has insisted that she is not duly concerned by the fact that she is not considered among the frontrunners to win the US Open.

Australia's Stosur caused a shock last year when she claimed the title ahead of big favourite Serena Williams.

Despite heading into the tournament with that victory under her belt, the bookmakers do not rate the 28-year-old as a likely candidate to repeat that feat at Flushing Meadows this time around.

However, Stosur does not believe that it matters who is ranked the favourite.

"It is what it is," Stosur said. "It's fine whether you're talked of as being the favorite or not.

"At this point during the tournament, it doesn't really matter. Everyone is starting from scratch, and obviously things become clearer as the weeks go on."

Stosur began the defence of her title with a 6-1 6-1 win over Petra Martic earlier today.