What a difference six years make.

In 2010, Kuomintang (KMT) rising star Eric Chu quit as Taiwan's youngest-ever vice-premier to challenge the Democratic Progressive Party (DPP) chairman Tsai Ing-wen in a race for the mayoralty of New Taipei City.

He defeated Ms Tsai, also a former vice-premier, and went on to become one of the most popular mayors of the city surrounding Taipei.

Fast forward six years, and the tables have turned. As KMT chairman, he walked up on stage last night looking grim.

In his second contest against Ms Tsai to become Taiwan's fourth elected president, Mr Chu had lost.

With his wife and party leaders by his side, the 54-year-old conceded defeat and announced that he was stepping down as party chief.

"I am sorry, I have let you down. We have failed. We did not work hard enough," he told his supporters, many of them in tears.

The election bloodbath, in which the KMT also lost nearly half of its parliamentary seats, hollowed out the KMT's leadership. Besides Mr Chu, KMT vice-chairman Hau Lung-bin and Taiwan's premier Mao Chi-kuo also resigned.

Indeed, this marked a change in fortunes for the once-dominant KMT, which has held its majority in the legislature since the first direct legislative elections in 1992.

But President Ma Ying-Jeou's rule from 2008 was riven with problems - infighting among different factions, and Mr Ma's unpopular economic and pro-Beijing policies.

So it was an uphill battle, or in Mr Chu's own words, "mission impossible...against overwhelming odds", when he replaced the unpopular deputy legislative speaker Hung Hsiu-chu as the KMT's presidential candidate just three months ago.

But the last-minute gamble did not pay off as Mr Chu never polled above 30 per cent in opinion polls.

Faced with the KMT's worst electoral defeat, Mr Chu vowed that the party will reflect on its mistakes. "We will do some soul-searching, listen to what the public is telling us through their votes and will play the role of a strong opposition."

Jermyn Chow