The seventh-seeded Ostapenko is playing her third Australian Open - she advanced to the third round at Melbourne Park a year ago.
In her first match at Rod Laver Arena since losing last year's final to her sister, Serena, Venus Williams lost her opener to Belinda Bencic 6-3, 7-5 and ensured the title won't stay in the family.
Bencic, who lost to Serena in straights sets at the same stage a year ago, said when she saw the draw she was prepared for another tough opener.
Bencic, who lost to Serena in straights sets at the same stage previous year, said she had received a huge confidence boost by having 19-time Grand Slam champion Federer rooting for her.
"She just played above and beyond", Williams said. "I think for me now it's not that great, but it's nothing to panic about, guys". "After the injury and the tough times it's really an wonderful feeling".
CiCi Bellis, the WTA's Newcomer of the Year, was also among the eight US women who were out by mid-afternoon - 16 are in the singles draw. "I just enjoy every match and show my best". "It's a long road and long season ahead". "I just have to give her credit". If I do months without playing an official match, it's always a little bit more hard. By the rankings, it was an upset, but by no means, this was an upset for Bencic, who was a former top-10 player as a teenager.
Williams departed for a bathroom break and, seemingly refreshed, struck back at the start of the second, breaking Bencic's opening service game.
But 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.
Bencic, who made her WTA Tour debut as a 14-year-old against Williams in Luxembourg in 2012, had never beaten the seven-time Grand Slam victor in four previous meetings.
The 20-year-old fresh off of pairing with Roger Federer at the Hopman Cup mixed-team event where Switzerland won the title. She returned on a roll, winning the next six points to hold serve and then clinch the set. She was assessed a code violation for taking too much time to return to the court - she was eating a banana. "Just give me a little bit to regroup and we will be okay". I think everyone else makes a bigger deal about it than what I do personally.
Schiavone has never really been a star - she is best known for denying Australia's Sam Stosur the French Open in 2010 and, perhaps by way of revenge by the Australian tennis gods, this was her fifth successive failure to win a match in Melbourne - but Williams, of course, brings much more to the table in terms of reputation and accomplishment as well as a perennial popularity so it is never a matter for celebration when she is made to look ordinary.
Stephens - seeded 13th - was upstaged by Zhang Shuai 2-6 7-6 (7-2) 6-2 as she was left searching for her first win since reigning supreme at Flushing Meadows last September. Jack Sock and John Isner, the No 8 and No 16 seed respectively, both suffered shock defeats while Ryan Harrison and Mackenzie McDonald were the only Americans to win out of 11 players in the opening session.
Vandeweghe was leading in her first set before a rain delay on Hisense Arena, and Timea Babos rallied to win 7-6 (4), 6-2.
"I'm not going to say it's one particular thing, but if I could play on an American hard court with different balls, then I'd probably be a lot happier. I'll come back next year and do it all over again".
Google app matches your face to a famous painting
It offers a suite of terrific features for those interested in art, but it's certainly not among Google's most widely used apps. After that's done, you're matched with several paintings, in a variety of artistic styles, that have an essence of your looks.