SEOUL, South Korea - Local wildcard Han Na-Lae scored just her second and biggest career WTA main draw win on Tuesday, steeling past No.3 seed Kristyna Pliskova, 6-4, 6-4, to reach the secound round at the KEB Hana Bank-Incheon Airport Korea Open.

"I watched and analyzed Pliskova’s game on Youtube," Han explained after the match, "and set up my strategies and tactics for the game. "Kristyna has good serves so I focused on not only my return games but also my serve games because, if I did not hold my serve, I could barely have chances to win the match."

Read more: Romanians Begu, Cirstea surge into Seoul second round.

Han led by a set and a break before Pliskova leveled the second set, but the 25-year-old lefty steadied her nerve to break for the third time in the match to clinch the upset after one hour and 24 minutes on court.

A fixture at her home tournament, Han won her maiden WTA main draw match back in 2014 in an all-Korean battle with Jang Su Jeong, and has tended to play her best tennis in South Korea, winning a ITF Pro Circuit tournament in her hometown of Incheon earlier this spring.

"I’ve got lots of confidence in my serve and my shoulder condition is much better than last year. However, I think I really need to improve my second serve. As you saw today, my first serve speed is around 160 km/h but my second serve speed is under 100 km/h. I really need to improve that."

Pliskova has been one of the game's most dangerous servers, regularly in contention for the mantle of season-ending ace leader - currently held by sister Karolina. Though she served seven aces against Han, she only managed a 53% first serve percentage, still trying to regain momentum after injuring her dominant hand at the Jiangxi Open in Nanchang.

Standing between Han and a spot in the quarterfinals is Spaniard Sara Sorribes Tormo, who advanced past Heather Watson in three sets on Monday.

"I won the first round so, now I’ll just focus on my next match then. One match, at a time!"

Elsewhere, the USA's Nicole Gibbs beat Jang Su Jeong, 6-3, 7-5, while Denisa Allertova got a straight-sets win against Andrea Petkovic, 6-2, 7-5. Top seed Jelena Ostapenko beat Johanna Larsson 7-6, 6-1 and Arantxa Rus surprised No.8 seed Christina McHale, 6-3, 6-4.

In an all-Netherlands clash, Richel Hogenkamp came out on top against Kiki Bertens, 5-7, 7-4, 6-3. Veronica Cepede Royg of Paraguay beat Peangtarn Plipuech of Thailand, 6-3, 6-2, and Nao Hibino got an equally comfortable win over Chang Kai-Chen, 6-2, 6-4.