Fourth seed Kristyna Pliskova, twin sister of world No 1 Karolina, fired down 14 aces to see off Taiwan's Chang Kai-chen in straight sets on Monday in the Japan Women's Open.

The Czech, a wildcard entry to the $250 000 Tokyo tournament, came through her first-round match 7-5, 7-5 despite a sluggish start in humid conditions.

"My serve helped me today," said Pliskova, who holds the record for the most aces in a match on the women's WTA Tour with 31.

"It's always tough after a Grand Slam – you don't know how you will feel," added the 25-year-old world number 41.

It was her first match since being edged out 7-6, 7-6 in the second round of the US Open in New York to Slovakia's Magdalena Rybarikova.

Pliskova next faces either Japan's Nao Hibino or a qualifier for a place in the quarterfinals of the hardcourt event.

Third seed Elise Mertens progressed with little fuss, the Belgian beating Russian Evgeniya Rodina 7-6, 6-1 while China's Wang Qiang saw off Taiwan's Hsieh Su-wei 7-5, 6-2.

Much of the focus on Tuesday will switch to Japan's Kimiko Date, playing in her final tournament just short of her 47th birthday.

The former world No 4 faces Serbian Aleksandra Krunic, at 24 comfortably young enough to be her daughter.