Melbourne - Sloane Stephens says she will not try not to "get too down" after becoming a big name casualty of the Australian Open on Monday.
The US Open champion, whose preparation for the first Grand Slam of the year was hampered by an ongoing knee injury, crashed out 2-6, 7-6 (7/2), 6-2 to Zhang Shuai in an error-strewn performance.
The American extended her losing streak since winning at Flushing Meadows in September to eight matches against the 34th-ranked Chinese number two, a surprise quarter-finalist in Melbourne two years ago.
Stephens came back from a long-term injury to record her US Open victory but has since endured fitness niggles which forced her out of her Sydney warm-up event last week.
"I did everything that I could to be ready for Sydney last week and for here," said Stephens when asked about her knee problem.
"It's just unfortunate, but it's definitely only the beginning of the season, first two tournaments. Not going to get too down.
"I'm just going to stay positive and keep working to get back in the best shape and best place possible to do well for my next tournaments."
Known as "Sloane Ranger", she had seemed in control as she raced to the first set 6-2 in 38 minutes.
But Chinese battler Zhang would not lie down and gradually got herself on top, winning the second set on a tiebreak for the loss of only two points.
She then scooted away to victory in an hour and 58 minutes over an increasingly frustrated Stephens who promised to bounce back.
"I'm going to beat someone eventually," Stephens said of her eight-match slump.
"I will have the best Instagram picture when I finally snap this losing streak."
Zhang, ranked 34, is one of the most popular players among her fellow WTA Tour pros and Stephens was full of praise for her conqueror.
"I love her," Stephens said. "She's great. I don't think one person doesn't like her."
Zhang reached the second round for the third year running after going all the way to the quarter-finals on her debut at Melbourne Park two years ago.
"She's a tough player," said Zhang of the American. "I know how hard I have worked so I'm ready for every match, every player. That's how I won."
She will next face qualifier Denisa Allertova of the Czech Republic who beat France's Pauline Parmentier 6-3, 6-0.