Kerber said: "It was not my day, completely not my day today".
"I'm always trying my best and also my team is trying the best, and I think this was also during the whole year I always had some small things that (prevented me from) playing my best".
Pliskova is scheduled for the first match on Ashe when the Czech faces Magda Linette of Poland. This time, she would not make the same mistake, in a devastating display of aggressive baseline tennis.
But perhaps it wasn't too surprising after Kerber played so poorly following her breakthrough 2016, when she also won the Australian Open and lost to Serena Williams in the Wimbledon final before ascending to No. 1 with her victory here.
Yet, Osaka felt nervous against Kerber in the 23,771-seat Arthur Ashe Stadium, having lost to American Madison Keys in the third round of the U.S. Open previous year after leading 5-1 in the third set.
"I think it's just the matches and how I played last year from the beginning and how I'm struggling this year".More news: Download Android Oreo 8.0 Wallpapers, Ringtones, Notification Sounds
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"I felt the same type of nerves come up, 4-1 in this match, so I wanted to tell myself just to keep playing how I was playing and not let the nerves get over me as much as last year", the 19-year-old Osaka said. I know that I will not give up like this. "So for me, I will try to forget the match as soon as possible and look forward again". Her win her erases bad memories of a loss a year ago at the U.S. Open, when she broke into tears as she watched a 5-1 final set lead over Madison Keys whittle away. Osaka made it to the third round at Wimbledon this year but has yet to win a WTA title.
"So the site feels really familiar to me". Osaka would close the match out with a break of serve in the seventh game, pushing through in just one hour and four minutes.
World number one Karolina Pliskova has headed in the opposite direction to Kerber after losing to the German in the final here past year and she eased into round two.
Pliskova said: "I was a little bit nervous this morning before the match".
"Obviously before every first-round match, I'm a little bit nervous, but especially in a Grand Slam and especially to defend so many points here from the final previous year".
"It was a little bit hard, but I think I made it pretty okay today".