The Workers' Party (WP), from its top echelon to its rank-and-file volunteers, was completely blindsided by the election results.
Indeed, at the end of the party's final rally at Bedok Stadium on Wednesday night, packed with supporters chanting the party's name, an insider close to the leadership told The Straits Times: "The voice for change is louder than in 2011. There won't be any Non-Constituency MPs in the next Parliament."
What went wrong for the WP?
One could simply be over-confidence. Sources say that the incumbents did not do much campaigning in Aljunied itself, thinking that the ward was in the bag.
In the run-up to Polling Day, candidates and activists alike shared with The Straits Times that the ground was sweet. Interactions with residents gave positive signs that there was a good chance to win in Fengshan SMC, East Coast GRC and possibly other constituencies too.
Thinking to build on this, party bigwigs took time to walk the ground in East Coast GRC and Fengshan to support their candidates.
Another factor could simply be lingering worries over the finances of Aljunied-Hougang-Punggol East Town Council (AHPETC).
The WP-run town council has been faulted for financial and governance lapses and People's Action Party (PAP) leaders have accused the WP of incompetent management of the town council.
The campaign against AHPETC started way before the General Election and during the first few days of campaigning, the PAP took aim at the WP, questioning the integrity of the leaders. WP leaders maintained that there was no wrongdoing and challenged the PAP to produce evidence of corruption.
But it is hard to say if the PAP strategy worked.
Candidates consistently said few residents questioned them over the town council's accounts. Similarly, most voters interviewed by The Straits Times said AHPETC did not figure at the top of their concerns when deciding who to cast their ballots for.
The biggest factor that helped the PAP cause in Aljunied was probably national and not local.
There were the feel-good effects from Singapore's 50th birthday celebrations as well as the death of founding prime minister Lee Kuan Yew, something PAP leaders have campaigned on in the nine days.
Both sides agreed the large voter turnout in support of the PAP was a decisive factor in the Aljunied battle.
Former Cabinet minister Lim Boon Heng, who advised the PAP team in Aljunied, said that the swing towards the PAP is an endorsement of the policies that it has implemented over the past few years.
"Some of these policies weren't so apparent prior to 2011 but it's become clearer to people that the Government is moving in the right direction. This swing tells the PAP leadership that it's doing the right thing. And of course this helped us in Aljunied," he said.
WP secretary-general Low Thia Khiang also agreed, but gave a different spin on the numbers.
For one thing, even though the WP lost a seat in Punggol East, he believed that WP managed to hang on to Aljunied GRC because it enjoyed strong support among voters.
"You win, you lose, that's part and parcel of life," said Mr Low, early this morning after his victory speech. "If you look at the result, it's a massive swing. The WP has done pretty well."
A look at the overall numbers supports this idea that WP still managed to retain its voters from the last GE. In this General Election, the ruling party's vote share went up to 69.9 per cent, a 9.8 percentage point improvement from 2011, when it scored its worst showing since independence.
The WP garnered 39.8 per cent of votes in the areas it stood in, a 6.8 percentage point slide.
There is still a considerable distance between the WP and the next best performing opposition party, the Singapore Democratic Party.
One question that the WP will have to answer is whether to take up the Non-Constituency MP posts that will be offered to it as Fengshan, Punggol East and East Coast had the best losing scores.
If the party takes up those posts, that would ensure nine opposition MPs - six elected and three NCMPs - with all of them from the WP.
That would give the party a decently strong platform to showcase its emerging leaders such as East Coast candidates Leon Perera and Daniel Goh.
In the meantime, WP will have to go back to the drawing board and figure out how to bounce back from this setback.