23 senators present and a quorum is declared, only Sen. Alan Peter Cayetano is absent. | via @adrianayalin #Du30SONA2016 — ABS-CBN News (@ABSCBNNews) July 25, 2016

Sen. Alan Peter Cayetano was a no-show at the opening of the 17th Congress on Monday, the same day that senators elected Senator Koko Pimentel as the new Senate president.

A total of 20 senators voted for Pimentel as the leader of the Upper Chamber, with three voting for Sen. Ralph Recto.

Cayetano, running mate of President Rodrigo Duterte, was earlier touted as a possible contender for the position of Senate President before majority of senators backed Pimentel for the position.

'Senate presidency a toss-up between Alan, Koko'

Senator Tito Sotto earlier said Cayetano did not want Senator Panfilo Lacson to be the head of the public order committee, Senator Loren Legarda to be the head of the finance committee, and Senator Manny Pacquiao as chairman of the committee on games and amusements.

Sotto: Cayetano had demands on Senate committee chairmanships

Cayetano also rejected Senator Leila De Lima, a former Justice secretary and a vocal critic of President Duterte, as the new head of the Senate justice committee.

Cayetano questions Pimentel's choices for committee chairs

Before the vote, Sen. Antonio Trillanes IV said it would not look good if Cayetano would want to join the Senate minority.

"Kung magiging minority siya, hindi magiging maganda ang dating. Parang, I believe it is childish and immature for him to do that kasi magkasama sila ni President Duterte," he said.

"[Bakit childish?] Kasi hindi niya nakuha ang gusto niya. Dapat he should be man enough to admit na he lost. He should move on."