People's Action Party (PAP) candidate Liang Eng Hwa edged out his Singapore Democratic Party (SDP) opponent Paul Tambyah to retain Bukit Panjang for the ruling party.
Mr Liang won 53.74 per cent of the votes, with Professor Tambyah garnering 46.26 per cent.
The contest between Mr Liang and the SDP chairman - an infectious diseases expert who has criticised the Government's handling of the Covid-19 pandemic - had been touted as a hot seat to watch.
Comprising about 160 Housing Board blocks and three condominiums, Bukit Panjang is the largest single seat with 35,497 registered voters. Since the single-member constituency was created in 2006, the PAP and SDP have faced off in four elections there.
In 2015, the PAP's Dr Teo Ho Pin won 68.38 per cent of the valid votes and in 2011, 66.27 per cent. In the 2006 General Election, the ruling party took home 77.18 per cent of the votes.
Mr Liang, 56, was fielded as the PAP candidate after Dr Teo, who held the SMC for three terms, announced he was stepping down.
Prof Tambyah, a professor of medicine at the National University of Singapore, made an unexpected switch from Holland-Bukit Timah GRC, where he had contested in 2015, in what was described as a "strategic decision" by the SDP.
Mr Liang also contested as part of the PAP team in the same GRC, in 2015. "It was a really tough contest and we really gave everything," he said early this morning.
"I'm really happy to have won this hard fought victory and hope I do my residents justice. We will work hard to carry out the plans that we have promised."
A managing director at DBS Bank, Mr Liang had emphasised at the hustings the projects he pushed for in his three terms as MP in the Zhenghua ward in Holland-Bukit Timah GRC, including the addition of bus services and the upgrading of the Bukit Panjang LRT.
These also benefited residents in neighbouring Bukit Panjang SMC, he said.
Throwing their weight behind him, Foreign Minister Vivian Balakrishnan and Ms Sim Ann, Senior Minister of State for Communications and Information, and Culture, Community and Youth, joined him for two walkabouts over the weekend, highlighting his ability to helm town council matters.
They tipped Mr Liang to be the chairman of Holland-Bukit Panjang Town Council if elected, and said there would be differences "residents can feel" if the joint town council were to be split should either constituency fall to the SDP.
Aside from municipal issues, Mr Liang pledged to speak up on national issues like manpower and foreign workers.
Other priorities set out in his manifesto include institutionalising flexible work arrangements, improving health insurance plans for locals and job creation.
Prof Tambyah, meanwhile, had focused mainly on the SDP's campaign slogan of "Four Yes One No".
Yes, to suspending the goods and services tax until the end of next year, retrenchment benefits for workers laid off due to Covid-19, a $500 monthly payment for 80 per cent of retirees and putting the people's interest first.
The single No was to raising Singapore's population to 10 million. During the campaign, the SDP became embroiled in a dispute over this 10 million target, which it accused the PAP of "toying with".
The PAP, however, rejected this suggestion as a falsehood aimed at misleading and frightening voters.
Prof Tambyah said early this morning: "We can hold our heads up high for a strong campaign considering the circumstances... Unfortunately, a miracle did not happen but we are grateful for the experience." He added: "I'm sure we can do better the next time."