Taiwan leader Tsai Ing-wen resigned as the head of the ruling Democratic Progressive Party (DPP) Saturday night after the party suffered a major electoral defeat on Saturday, losing two of the island's most important city posts in mayoral elections.

The DPP lost control of the mayoralties in Taiwan's second-most populous city Taichung and the key battleground of Kaohsiung in the south, which it held for two decades.

The DPP has now been left in control of only six of Taiwan's cities and counties, compared with 15 for the opposition party Kuomintang.

Read more: Taiwan's local election results announced

The party carried two of its other strongholds, however, keeping Tainan in the south and Taoyuan in the north.

Voters in Taiwan headed to the polls on Saturday in local elections, commonly known as the "nine-in-one" elections. More than 11,000 seats were up for grabs in municipalities, counties, townships and villages. Voters were also being asked to vote in 10 referendums. 

Analyst: Tsai's performance is a failure

The DPP will suffer from the landslide defeat, said Zhong Houtao, Assistant Researcher at the Institute of Taiwan Studies, Chinese Academy of Social Sciences. 

When discussing the result of Saturday's elections, Zhong said most observers predicted that the DPP would perform poorly but failed to see that it would lose so badly.

He said one of the reasons for DPP's unprecedented failure is that the party was not able to solve issues such as corruption scandals and reduction in benefits. 

Zhong described Tsai's administrative performance in being Taiwan's leader over the two years as a failure. 

According to the latest survey, the majority of the people in Taiwan are not satisfied with Tsai's performance, Zhong added.