MANILA - The ouster of Davao del Norte Rep. Pantaleon Alvarez as House Speaker and the rise of Pampanga Rep. Gloria Macapagal-Arroyo in his place was proof of the power of Davao City Mayor Sara Duterte-Carpio, an opposition lawmaker said Wednesday.

A day before her father President Rodrigo Duterte delivered his third State of the Nation Address, Mayor Duterte managed to rally majority of House members and convinced Alvarez's supposed "supermajority" to oust him as Speaker, ACT Teachers Party-list Rep. Antonio Tinio told reporters.

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"Alam ng lahat si Mayor ang tumatawag sa mga kongresista para suportahan si Speaker Arroyo. Hindi siya pangulo. Anak siya ng pangulo. Pinakita niya ang poder at impluwensiya niya sa kongreso," Tinio said.

(Everybody knows that it was Mayor Duterte who called congressmen to support Speaker Arroyo. She is not the president. She is the daughter of the president. She just showed Congress her strength and influence.)

Alvarez drew the ire of the President's daughter after he allegedly called her a part of the opposition after she formed a regional party that excluded the former Speaker and his allies.

"He is calling mayors in the region telling them that I am opposition, I have a feud with my father and that I am acting alone," Mayor Duterte earlier told ABS-CBN News when asked about the online rants she posted against Alvarez.

"This insecure fat sleaze is the epitome of the idiom barking at the wrong tree. I am not interested in his politics but he fired the first shot," she said.

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The Davao City Mayor earlier twitted Alvarez by publicly daring him to step down from his post and saying that "the Philippines will be a better country if he is not Speaker."

"I thought you had backed down? But when I woke up today, why are you still the House Speaker? Step down!," Mayor Duterte said.

""The Philippines will be a better country if he is not Speaker. PRD will be a stronger President without Alvarez," she said.

'Nobody saw it coming'

Oriental Mindoro Rep. Reynaldo Umali said it was this rift that caused Alvarez the speakership.

"Nobody saw it coming, it happened too fast. To my understanding there were calls made Sunday night, that's about it," Umali said.

• Alvarez's rift with Sara Duterte led to ouster: Umali

Mayor Duterte has repeatedly declined to comment on the House leadership change.

She instead congratulated Arroyo and called her a "strong leader."

• Sara Duterte congratulates Arroyo, calls her 'strong leader'

GMA a bystander?

Arroyo's allies in the chamber claimed that the former President did not connive with anyone to grab the leadership away from Alvarez.

"She was an innocent bystander," House Minority Leader and Arroyo's long-time ally Danilo Suarez told ANC's Early Edition.

Suarez said the House coup was a "cohesive action of key leaders of 3 different political groups" in the chamber.

He said the lawmakers were not happy because Alvarez declared a no-election scenario for 2019 and withheld funding from some House members, he said.

Ang Kabuhayan Party-list Rep. Dennis Laogan added that there have been efforts before to unseat Alvarez but Arroyo declined to take part in it as she was looking forward to her retirement since she is on her last term as Representative of the 2nd district of Pampanga.

"They make it appear that she was this power hungry woman who just wants to be back in power," Laogan said in a statement.

"It's tasteless and shameful because from what I know, it was the concerted effort of the majority of the house that wanted to have a new Speaker," he said.

It remains unclear what changed Arroyo's mind this time around.

- with a report from RG Cruz, ABS-CBN News