Fujimori is the eldest daughter of former president Alberto Fujimori.
Meanwhile, there are also those who fear that Pedro Castillo, a primary teacher who was little known before winning the first round of the election, could destabilise Peru's economy.
Ms Fujimori herself spent several months in custody on corruption allegations she denies.
Her father is serving a 25-year sentence for crimes against humanity and corruption.
Whoever wins will take leadership of a nation in crisis, suffering from recession and with the worst coronavirus fatality rate in the world after recording more than 1,84,000 deaths among its 33 million population.
Peru's presidential run-off on Sunday will be the Andean country's most polarised election in its recent history.
While he has vowed to respect private property, he also proposes to renegotiate tax contracts with large mining companies, which play a key role in the economy.
He is from a remote village near the town of Tacabamba, in Peru's northern Andes, which on Saturday night cheered him as he made his way back home to vote.
The city government installed a stage in the main square, which was filled with supporters and music. Both Mr Castillo and Ms Fujimori condemned the attack.
Peruvians will also look to the victor to end years of political turbulence after four presidents in the last three years, and with seven of the last 10 of the country's leaders either having been convicted of or investigated for corruption.
Mr Castillo was the unexpected victor of the first round in April, which saw votes split among a wide field of candidates.
Last November, the country cycled through three presidents in just a few days, a political crisis that sparked fierce protests and left several people dead.
Nevertheless, she scraped into the runoff by taking just 13 per cent, in a field of 18 candidates, to Castillo's 19 per cent. "Keiko's only possibility of growing her support was to create a monster, and she has been extremely successful", says Giovana Peñaflor, of Imasen pollsters.
Pollsters say undecided voters and Peruvians living overseas could tip the balance in the crunch poll.
Overseas Peruvians make up nearly 4% of the 25 million on the electoral roll. Normally, few of them vote - only 0.8 per cent in the first round of the election in April, when COVID-19 lockdowns were commonplace.
Peruvian electoral authority ONPE said so far it had counted 42% of the vote.
A neck-and-neck result could lead to days of uncertainty and tension if it takes time to settle on a victor.
The teacher, who likes to campaign in a cowboy hat and often carries an oversized pencil - the symbol of his Free Peru party - won almost 19% of the votes, followed by Ms Fujimori with 13.4%.
Apple won't force updates to iOS 15 from iOS 14
For those who want to keep an eye on their physical fitness, meanwhile, a Trends feature will let them know how they're doing. Apple will provide an alternative way to help senders bypass the DND mode for truly important messages, though.