MANILA - When two equally volatile and unpredictable presidents are put in the same room, will they hit it off or will sparks fly?

The question is being asked here with brash billionaire businessman Donald Trump's election as the next President of the United States. Most Filipinos had hoped to see Democrat Hillary Clinton elected, as she was supposed to represent continuity and stability.

There is also a palpable sense of uncertainty about relations between Manila and Washington, already frayed by Philippine President Rodrigo Duterte's anti-US tirades.

Mr Duterte was en route to Kuala Lumpur for a state visit on Wednesday (Nov 9) when he received word of Mr Trump's victory.

In a statement read out by his communications minister subsequently, Mr Duterte said he "looks forward to working with the incoming administration for enhanced Philippines-US relations anchored on mutual respect, mutual benefit and shared commitment to democratic ideals and the rule of law".

Said political analyst Richard Javad Heydarian, of De La Salle University: "Clinton would have been a far better option."

With Mr Trump now at the helm, the Philippines can expect a few surprises, both good and bad, he added.

Mr Duterte, for instance, can expect the US, under Mr Trump, to ease up on its criticism of his violent and controversial anti-crime drive.

The Philippine leader has rained an almost daily torrent of insults at the US, as State Department officials call him out for more 2,000 people killed during police operations or by unnamed vigilantes since he took office on June 30.

"A Trump administration would most likely not be concerned with human rights issues," said Mr Heydarian.

He added he also does not see Mr Trump pressuring Mr Duterte to adopt an anti-China policy.

"We might see an America that is more concerned with striking a grand bargain," he said.

But Mr Trump can call Mr Duterte's bluff if the Philippine leader remains relentless in insulting the US, and pull out US troops in the Philippines.

Mr Trump had said Mr Duterte showed "lack of respect" in calling the outgoing US President Barack Obama a "son of a whore".

Mr Duterte has said he wants an end to all US-Philippine war games, and for all remaining American forces to leave the Philippines in two years.

His defence minister Delfin Lorenzana, though, has clarified that the military drills will just be scaled back, and that Mr Duterte has signed up on a 10-year defence pact allowing the US to rotate its troops in at least five military bases in the Philippines.

Mr Heydarian said the "transactions-oriented" Mr Trump could look at a "poor, developing country" like the Philippines, the US' treaty ally since 1951, as a "liability".

"Trump has consistently made the argument that if allies are not standing up for themselves, then what's the point of America standing up for her allies?" he said.

Defence analyst Jose Antonio Custodio does not expect a big shift in US foreign policy, despite Mr Trump declaring that the US should be compensated for the protection it gives its allies.

"It's not a whimsical matter… Remember, Trump is a businessman, and a businessman is known to be more prudent, more circumspect, especially in their dealings," said Mr Custodio. He said national security will continue to be a "core concern" for the US.

"It will remain constant, regardless of whoever is in the White House because defending American primacy is the main national security objective of all administrations that have occupied the White House," said Mr Custodio.

He said the US, under Mr Trump, would continue to defend its interest in the South China Sea and push back against efforts by China to exert greater influence in the region.

"Security is security, and the state needs to be protected. If you want to have a great nation, you have to protect your interest in a globalised world," he said.

Among call centres, meanwhile, there is a sense of unease.

The government's chief economic manager Ernesto Pernia said the Philippines' burgeoning business process outsourcing (BPO) industry, a key economic peg, could take a hit under Mr Trump, who has vowed to bring jobs outsourced by American companies abroad back to the US.

Nearly three-fourths of the BPO industry's earnings come from the US.

BPO companies, many of which are American-owned, brought in US$22 billion (S$30.8 billion) in revenues and employed over a million workers in the Philippines last year.

But for economist Peter Wallace, Mr Duterte and Mr Trump will surprisingly get along well.

"I think President Duterte will understand the kind of person Mr Trump is and be able to work with him. I think it may be good," he said.