MANILA, Philippines - Former Philippine leader Joseph Estrada insisted Monday he could cause a major upset and win next week's presidential election, as he slammed the frontrunner for threatening a popular uprising if he lost.

"That is very crazy," Estrada told reporters, reacting to warnings from favorite Benigno Aquino III's camp that his supporters would go to the streets if his huge lead in opinion polls was not reflected with an election triumph.

"He must not be so presumptuous as to claim a premature victory, and worse, threaten mass action if he does not win the elections."

Aquino's mother, Corazon Aquino, famously led the 1986 "people power" revolution that crushed dictator Ferdinand Marcos' brutal 20-year regime.

She eventually became president, and is revered for restoring democracy to the Catholic nation.

"He might want to take a lesson from his mother to speak with more humility. After all, the race is not yet over. May the best man win," said Estrada, 73.

Estrada was himself ousted by a military-backed revolt in 2001 after being accused of massive corruption during his three years in power.

He was convicted of graft in 2007 but quickly pardoned by his successor, Gloria Arroyo, and is now aiming to stage a stunning political comeback in the May 10 election.

Aquino is enjoying a huge lead with 39 percent support, independent pollster Pulse Asia said last week as it released its final survey before the election.

But the survey also showed former movie action star Estrada's popularity rising to 20 percent, tied for second place with business titan Manny Villar.

Estrada said his own surveys showed that he was trailing Aquino by only 10 percentage points, with 25 percent of the country's 50 million voters expected to pick him, and that he would continue to gain support over the next week.

"Aquino's numbers have reached a plateau, Villar's are on a nosedive, while mine are on a steady, upward trajectory," Estrada said.

Aquino on Monday again raised the prospect of a popular uprising should he lose.

"Clearly there is a majority with us, and if their voices are not heard, they will take the appropriate action," he told reporters while on the campaign trail in the eastern Philippines.

"We will hopefully avoid a situation that is as interesting as the 1986 elections."