The People's Action Party-held Mountbatten single seat will once again be contested by two lawyers.
Mr Lim Biow Chuan, who is hoping to make it three wins in a row at the Sept 11 polls, will need to stave off the challenge from Mrs Jeannette Chong-Aruldoss.
The 52-year-old mother of four, who had contested under the National Solidarity Party (NSP) banner previously, had a credible showing at GE2011, taking 41.4 per cent of the vote to Mr Lim's 58.6 per cent.
Yesterday, she filed her nomination papers at Kong Hwa School to contest in the ward as a candidate for Singapore People's Party (SPP).
Although her party colours have changed, she asked voters yesterday to judge her on the grassroots work she has been doing over the last four years despite her loss.
SERVING THE RESIDENTS
We have worked very hard for the past four years and we will continue to work hard to win the support of Mountbatten residents.
MR LIM BIOW CHUAN, PAP candidate for Mountbatten
"I'm ready to be judged on my merits and my capabilities, but the final outcome will be determined by the majority," she said.
Accompanied on stage by her husband James Aruldoss, 56, and 22-year-old daughter Elisabelle, she said her desire to serve Mountbatten voters has grown only more "intense and more urgent" over the last four years.
"I will be your tireless MP in Mountbatten and your fearless fighter in Parliament," she said.
She had unveiled her manifesto for the ward on Monday, pledging to keep rental prices affordable for food stallholders; establish a social mobility bursary for students making the transition from the Institute of Technical Education to polytechnic, and from polytechnic to university; as well as push for Dakota Crescent to be conserved.
Her opponent, Mr Lim, who is also 52, has said that national issues, such as housing, transport and population, will be his focus if he is elected to Parliament.
Speaking at Kong Hwa School in both Mandarin and English, the PAP candidate said: "United, you and I can do a part for the country and the people...
"We have worked very hard for the past four years and we will continue to work hard to win the support of Mountbatten residents. "
He declined to reveal more details about his campaign rally plans when asked, but said his team was "ready to fight".
Both candidates in this widely expected match-up had their share of backers at the nomination centre.
One of Mr Lim's supporters, engineer Daniel Tan, 43, said he always "made sure needy people who required help for education funds got it quickly".
Businessman Robert Ong, 59, who supports Mrs Chong-Aruldoss, said Singaporeans need more people like her.
He added: "We need people in Parliament to represent Singaporeans, not just toe their party line."
- Additional reporting by Olivia Ho