Mona Barthel’s Australian Open campaign might be in jeopardy with the world No.45 having to resort to painkillers to win through to the quarter-finals of the Hobart International.

Playing a backhand in the fourth game of her clash with Japan’s Naomi Osaka on Wednesday, the 25-year-old felt a pinch in her lower back and quickly sought treatment.

“At the beginning, I was like ‘wow, this is a lot of pain’,” she said after her 7-6 (7-2) 6-2 win.

“I was just trying to play and take it one point at a time.”

The new complaint comes just a week after Barthel’s withdrawal from the Auckland women’s classic with a gastro illness and the player wonders if her body is still run down and susceptible to problems.

“I feel like stretching to a ball was really tough for me and rotating so a lot of movement in the back was tough.”

The 2012 Hobart champion will undergo intense treatment ahead of her quarter-final with France’s Alize Cornet and says it’s too early to know what impact the injury could have on her Melbourne grand slam ambitions.

“You never know – sometimes you wake up tomorrow and maybe everything is gone or maybe it is worse,” Barthel said.

“I’m positive and I’m thinking that it gets better.”

In other action, qualifier Kiki Bertens scored an easy 6-3 6-1 win over Germany’s Annika Beck.

Day-four at the Hobart International includes Gold Coast teenage wildcard Kimberly Birrell who faces a tough second-round challenge against world No.37 Dominika Cibulkova.

Later on Wednesday, defending champion Heather Watson meets tournament No.4 seed Monica Niculescu.