The first day at the Toray Pan Pacific Open was particularly successful for the qualifiers, with up to 3 qualifiers advancing into 2nd round.
The first match of the first day was supposed to be the most interesting of the first round matches, but it didn't happen. Anastasija Sevastova withdraw from the tournament, so lucky looser Osuigwe presented herself against Elise Mertens. Mertens handled the match smoothly in two sets 6-3 and 6-1.
The first surprise took place in the second match, when qualifier Gibbs surprised the 32nd woman in the
WTA ranking Riske. Gibbs won 6-4 and 6-3 in less than 2 hours and will meet Angelique Kerber in the second round.
We saw a surprise also in the match, whose winner will play Naomi Osaka in the 2nd round. Cornet and Tomova fought for nearly 3 hours in the match, which was surprisingly won by the Bulgarian. After the first set loss, she turned the match and defeated the more experienced Alize Cornet.
Dayana Yastremska also failed to advance into the 2nd round, when she succumbed to Pavluchenkova 6-3 and 6-1 in less than an hour and added the second loss in a row.
Full Day 1 results in Osaka:
| | | Mertens E. (Bel) | 2 | 6 | 6 | | | | | | |
| Osuigwe W. (Usa) | 0 | 3 | 1 | | | | |
|
| | | Riske A. (Usa) | 0 | 4 | 3 | | | | | | |
| Gibbs N. (Usa) | 2 | 6 | 6 | | | | |
|
| | | Han X.Y. (Chn) | 0 | 66 | 1 | | | | | | |
| Giorgi C. (Ita) | 2 | 78 | 6 | | | | |
|
| | | Cornet A. (Fra) | 1 | 6 | 3 | 2 | | | | | |
| Tomova V. (Bul) | 2 | 4 | 6 | 6 | | | |
|
| | | Puig M. (Pur) | 0 | 0 | 3 | | | | | | |
| Diyas Z. (Kaz) | 2 | 6 | 6 | | | | |
|
| | | Yastremska D. (Ukr) | 0 | 3 | 1 | | | | | | |
| Pavlyuchenkova A. (Rus) | 2 | 6 | 6 | | | | |