Jessica Ennis-Hill dismisses favourite talk for Games
The Brit secured her one and only Olympic medal in London four years ago, but appears to have a fight on her hands to go back-to-back.
Ennis-Hill was seventh in the women's long jump at the Anniversary Games on Saturday, with Katarina Johnson-Thompson winning the event.
The 30-year-old acknowledged the difficulty of the task awaiting her in Brazil.
"I haven't got the world lead and I didn't compete in Gotzis," Ennis-Hill said.
"There are quite a few girls who have upped their game this year. I don't feel like the favourite."
A jump of 6.19 metres saw Ennis-Hill finish seventh on Saturday, well behind the mark set by Johnson-Thompson (6.84m).
However, Ennis-Hill jumped 6.63m in Ratingen, Germany, in June and hopes she can manage that again at the Olympics.
"Having jumped 6.60m a few weeks ago I'd hoped to jump that again," she said.
"I've got a couple more weeks to get everything right. I hope to bring it all together in Rio. That's when it matters."