WASHINGTON, Oct. 5 (Xinhua) -- Senate Republicans appear to have secured enough votes for the confirmation of President Donald Trump's Supreme Court pick Brett Kavanaugh, as key Republican Senator Susan Collins said on Friday that she will vote yes despite bitter partisan fights over sexual assault allegations against the judge.

It now appears that there will be 51 votes in favor of Kavanaugh, since Democratic Senator Joe Manchin of West Virginia came out minutes after Collins' announcement, the only Democrat to back Trump's nominee.

Only one Republican, Senator Lisa Murkowski of Alaska, is expected to vote against Kavanaugh.

The Senate is expected to hold its final floor vote on Saturday. It's widely thought that Kavanaugh's confirmation to the Supreme Court would give Republicans a win that lasts at least a generation.

In a speech lasting more than 40 minutes, Collins said she believed Kavanaugh was well qualified and she cannot abandon the "presumption of innocence" over the sexual assault allegations against the nominee.

Meanwhile, the senator from Maine slammed the confirmation process "looks more like a caricature of a gutter-level political campaign".

"Our Supreme Court confirmation process has been in steady decline for more than 30 years. One can only hope that the Kavanaugh nomination is where the process has finally hit rock bottom." she said.

As Collins stepped onto the Senate floor to make her speech, protesters in the Senate gallery chanted loudly, "Vote No! Show up for Maine women! "

Earlier on Friday, the Senate wrapped up the debate on the confirmation in a procedural vote along partisan lines, paving the way for the final vote.

A FBI report sent to the Senate on Thursday said that based on its one-week supplemental background investigation, there is no corroboration of sexual misconduct allegations made against Kavanaugh.

White House and Republican Senate leaders said the FBI report revealed no evidence of wrongdoing, while Democrats said the White House tied the FBI's hands and the probe is not thorough.

In a Quinnipiac poll issued on Monday, 48 percent of Americans said that Kavanaugh should not be confirmed to the Supreme Court, while 42 percent said he should be confirmed.

Three women have come forward to accuse Kavanaugh of sexually assaulting or harassing them during his high school and university years. Kavanaugh has denied all the accusations.