Veronika Mendoza, a 35-year-old leftist presidential contender in Peru who is promising a new constitution to weaken the country's business elite jumped 5 percentage points in a poll and was seen as statistically tied at second with investor-favourite Pedro Pablo Kuczynski.
Lawmaker and psychologist by training, Mendoza would win 17.3% of valid votes in the April 10 election, compared with Kuczynski's 18.6%, according to a poll published on Friday by local pollster Datum International.
Long time front-runner Keiko Fujimori, the daughter of imprisoned ex-president Alberto Fujimori, was 8 points short of the 50% minimum needed to win outright, according to the results, which excluded the 14.2% of blank or spoilt ballots.
The March 28-30 survey of 1511 people, who received and filled out simulated voting cards, has a margin of error of 2.5 points.
The Datum poll was the first to show Ms. Mendoza head-to-head with ideological opponent Kuczynski for second place, which would allow either of them to tap a resurgence of opposition to Ms Fujimori in a likely June run-off.
However, Ms Fujimori would beat Ms Mendoza by 10 points in a second-round contest with 18% of voters undecided, according to Datum. Ms Fujimori and Mr Kuczynski were seen in a dead-heat with 41 and 40% of voter intent respectively.
Ms Mendoza has proposed replacing the 1993 constitution, enacted by Alberto Fujimori after he shuttered Congress, with a new one that would allow the government to be more active in the mining-fuelled economy.
Do we want to keep dragging around a constitution written by a dictatorship to guarantee privileges for a few at the expense of the vast majority? Ms Mendoza said at a press conference earlier this week. We want deep and true change, we want radical change, she said.
Ms Mendoza had just 1% of support in opinion polls a month ago and started to climb after two leading candidates were tossed out of the race for breaking electoral rules in a controversial ruling that turned the race on its head.
She was the only leading candidate who climbed in the Datum mock vote from the last one conducted March 17-20. Ms Mendoza's rise follows widespread criticism of Kuczynski after he said Ms Mendoza had never done anything in her dog life.
Ms Mendoza broke with President Ollanta Humala, a former radical military officer, after he turned to the right upon taking office in 2011. Humala's term ends July 28, and he is constitutionally barred from seeking a second consecutive term.