Seoul, Sep 26 : Former South Korean Prime Minister Lee Nak-yon has won a key battleground region to claim his first electoral victory in the ruling Democratic Party (DP)'s primary for the 2022 presidential election. The former party chairman garnered 47.1 per cent of the 71,835 votes cast by registered party members in the Gwangju-South Jeolla Province region, defeating Gyeonggi Governor Lee Jae-myung by a razor-thin margin of 0.2 percentage point, according to the election results released on Saturda. The former Prime Minister's victory in the Gwangju-South Jeolla Province region, a key electoral stronghold of the liberal party, snapped the winning streak of the Gyeonggi Governor, who won all the four previous regional primary votes by a landslide margin, reports Yonhap news Agency. Former Justice Minister Choo Mi-ae came in third, winning 4.3 per cent of the votes, followed by Rep. Kim Du-kwan with 0.9 per cent and Rep. Park Yong-jin at 0.6 per cent. Lee Nak-yon is pinning hope on the remaining course of the primary, particularly the regional vote in North Jeolla Province on Sunday, to reverse the race in his favour. The DP is required to hold an additional run-off vote, pitting the frontrunner against the runner-up to pick its single candidate for the March 9, 2022, presidential election if none of the five candidates wins a majority vote in the ongoing 11-leg competition that will wrap up in Seoul on October 10. /IANS