Pimentel said not one of his rivals from the opposition or the administration coalition has the 13 votes needed to unseat him.
"And this is giving them nightmares," he said.
As this developed, Sen. Rodolfo Biazon said there are now 11 senators supporting the bid of Sen. Edgardo Angara for the Senate post, further boosting the opposition’s chances of prevailing over the administration party in the leadership race.
Pimentel explained that unlike the House Speaker who must be elected at the start of every Congress, the Senate president continues to be in office until an aspirant succeeds in coming up with 13 votes to unseat the incumbent.
He downplayed claims by the opposition that it has the numbers to bag the top Senate post.
"Those claiming to have numbers are guilty of fuzzy math," Pimentel said. "The Senate race is lopsided in my favor."
Pimentel’s rivals from the administration People Power Coalition (PPC) include Senators Renato Cayetano, Franklin Drilon and Joker Arroyo.
Cayetano is assured of the support of five Lakas members while Arroyo has reportedly garnered support of four neophyte senators. Drilon supposedly has President Arroyo’s backing – a report which has been denied by Malacañang.
Cayetano said all aspirants have agreed to meet and come up with a single nominee when the first regular session of the 12th Congress starts on July 23.
He refused to identify the three "recruits" or the reason why they decided to join their cause.
Biazon also declined to discuss the alleged "inducements" offered by the opposition to the three senators, saying only that "no carrots were dangled."
He was confident, however, that the opposition would get the Senate majority in the 12th Congress.
Biazon also reiterated a previous statement by Angara that the opposition bloc in the Senate will pursue a critical cooperation stand with the Arroyo administration.
Earlier, Angara said the opposition is even willing to sit down with leaders of the administration in identifying the problems besetting the nation, and in determining the solution.
Biazon said there would be no "obstructionism" in the Senate even if the opposition controls the chamber.
"We understand the critical problems of the nation and we should help the Philippines bounce back," he explained.
Meanwhile, Vice President Teofisto Guingona urged PPC senators not to cross over to the opposition, saying they need to be united to ensure the victory of a partymate seeking the chamber’s highest position. – With Pia Lee-Brago, Marichu Villanueva