Hundreds of left-wing protesters rallied outside a venue where US President Barack Obama and other leaders of the 21-member Asia-Pacific Economic Cooperation (APEC) group were meeting.
The rally edged towards violence when protesters tried to break through lines of police, who were carrying riot shields and wooden batons, to reach the summit venue.
Police responded by firing water cannons and scuffled with protesters who were chanting: "Junk APEC".
Then police pulled out their secret weapon: pop princess Katy Perry on giant loudspeakers.
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Dolly Parton's "Islands in the stream", David Guetta's "Sexy bitch" and the Bee Gee's "How deep is your love" were among the other songs deployed against the protesters.
To add a street bass beat, some of the police tapped their batons against their shields in time with the music.
"It's ridiculous," leftist member of parliament Carlos Isagani Zarate told AFP, as the protesters retreated to soul classic "My Girl".
Many other protesters also expressed anger at authorities trying to suppress their message of opposition to globalisation and free-trade policies championed by APEC.
But others could not hide their amusement.
"That was a rude and desperate move," 54-year-old rice farmer Redo Pena told AFP as he broke into a toothless grin.
Metro Manila police spokeswoman chief inspector Kimberly Gonzales told AFP the music was aimed at de-escalating tensions.
"Filipinos in general love music and it has a calming effect for everyone. This goes well with our maximum tolerance policy during protests," Gonzales said.
The Philippines has a famous music culture, with karaoke one of the most popular forms of entertainment across all sectors of society.
Filipino musicians are also a staple of hotel and cruise ship bands around the world.
And prisoners at the main jail in Cebu, the Philippines' biggest city, have become an Internet sensation by posting videos on Youtube of them dancing to Michael Jackson's "Thriller".
Police spokeswoman Gonzales said using music at protests was not an unusual tactic, and there was no intent to trivialise Thursday's rally.
The protests occurred as Philippine President Benigno Aquino was welcoming Obama, Chinese President Xi Jinping and other leaders for the summit's second and final day.