In his address to parliament last year, two days after Jacob Zuma had resigned from office, Ramaphosa vowed a "new dawn", promising economic revival and to fight endemic corruption, earning him plaudits even from the opposition benches.
But, a year later, growth is tepid and unemployment remains stubbornly high at more than 27 percent while embarrassing details of corruption within the government and ANC ruling party officials have emerged.
An ongoing commission into graft has heard blow-by-blow details of how bribes were paid to several government and party officials, including senior cabinet ministers serving in Ramaphosa's government.
Mineral resources minister Gwede Mantashe and environment minister Nomvula Mokonyane are some of the top party guns whose names have been linked to corruption by witnesses at the graft hearings.
Ramaphosa is under pressure to move against the implicated officials, but he must also ensure the party maintains some unity through the election.
"The truth that is coming out will set us free and will make us stronger but we must make sure the wrong things being talked about in the commission must never, ever ... happen again in South Africa," Ramaphosa said at an ANC meeting last weekend.
- Battle for votes -
The opposition has jumped onto ANC corruption as a election trump card.
"Corruption is in the very DNA of the ANC," said Mmusi Maimane, leader of the main opposition Democratic Alliance. "We urge the president to act, and act fast".
Radical leftist opposition leader Julius Malema has challenged Ramaphosa to explain his links with Bosasa, a company that corruptly won huge government tenders under Zuma's tenure.
Ramaphosa is alleged to have benefited from Bosasa donations when he campaigned for the ANC presidency in 2017.
"If Cyril thinks he is going to do what Zuma was doing in that parliament, we will treat him the same way we treated Zuma," warned Malema, whose MPs booed and shouted down Zuma whenever he addressed parliament.
"Ramaphosa's own position is precarious as he attempts to lead a clean-up of government within a divided ruling party," said Judith February, a researcher with the Pretoria-based Institute of Security Studies.
He also faces pressure from beyond the borders of Africa's most advanced economy.
The Sunday Times at the weekend reported that five countries -- the US, Britain, Germany, the Netherlands and Switzerland -- had written a note to his office last year urging him to ensure full respect for the rule of law if he wanted to attract investment.
The economy is forecast to have grown less than one percent last year, and huge debts racked up by state-owned companies such as power-monopoly Eskom and South African Airways are a major headache for Ramaphosa.
"Given that most are in disarray, Ramaphosa needs to spell out how he will deal with corruption, and get them back on track," said February.
Ramaphosa is also expected to give an update on the controversial land reform plans to tackle apartheid-era inequality through "expropriation without compensation", which spooked foreign investors.
"The time has come for the president to move beyond the endless gimmicks and buzzwords that are taking us nowhere," wrote economist Duma Gqubule in a newspaper column.
Despite the falling recent support, the ANC is tipped to win the parliamentary election with around 60 percent of the votes, according to surveys conducted late last year.