By Stephen Collinson and Clare Foran, CNN

(CNN) -- Republican Sen. Susan Collins announced she will vote for Brett Kavanaugh, essentially ensuring that the controversial Supreme Court nominee has enough support to be confirmed when a final vote takes place Saturday.

Collins' announcement in a lengthy floor speech came after Kavanaugh survived, 51-49, a dramatic procedural vote that could have effectively killed his nomination after sexual assault allegations were made against him.

Collins and Flake, along with Democratic Sen. Joe Manchin, voted to advance the nomination. The final vote is expected Saturday.

One wavering Republican, Sen. Lisa Murkowski, defied her party and voted against advancing the nomination, and declared that she will vote against Kavanaugh's confirmation Saturday as well

"He's not the right man for the court at this time," she told reporters.

Flake said he will back Kavanaugh unless something changes. Asked how he will vote, he said "yes, unless something big were to change. I don't see what would." The Arizona Republican had forced a one-week delay and an extended FBI investigation into Kavanaugh.

Kavanaugh's candidacy has stirred a furious political debate and whipped up protests and recriminations and a clash between the mostly male power structure of the Republican Party and the emerging influence of the #MeToo movement which has become an important force in liberal politics.

Should he be confirmed, Kavanaugh could cement a conservative majority on the Supreme Court for a generation and represent a political triumph for Trump and a lasting dividend for an era of Republican power in Washington.

The outcome of the cliffhanger vote was in doubt right up until senators raised their hands or announced their votes, as they sat quietly in their desks in an unusual ceremonial scene that epitomized the gravity of the moment.

The only way that the vote could have been closer was if the final tally had been 50-50 -- in which case Vice President Mike Pence would have been called upon to break the tie in favor of Kavanaugh.

A final floor vote on Kavanaugh's nomination will finally resolve a confirmation process that was consumed by partisan outrage after the emergence of allegations that Kavanaugh assaulted Christine Blasey Ford while they were teenagers in the 1980s in suburban Washington DC.

Kavanaugh repeatedly denied the allegation, but emotional testimony Ford delivered to the Senate Judiciary Committee last week, and the judge's own explosive and partisan performance raised doubts about his temperament and left his hopes hanging by a thread.

In the tense moments before the morning vote, Senate Majority Leader Mitch McConnell, for whom a conservative Supreme Court majority would represent a career defining achievement, accused Democrats of trying to derail Kavanaugh's nomination with delaying tactics and obstruction-- even though he is a possibly Washington's most accomplished master of the dark arts.

"We know the Senate is better than this, we know the nation deserves better than this," McConnell said. "Let's seize the golden opportunity before us today, confirm a Supreme Court justice who will make us proud."

Had the vote fallen short, it would have dealt a major blow to the nomination and throw the possibility of confirmation into serious doubt.

There was immense relief at the White House where Trump watched a vote that takes him one final step closer to becoming the Republican president who enshrined a conservative majority on the Supreme Court -- an achievement that will elevate him in history.

"Very proud of the U.S. Senate for voting 'YES' to advance the nomination of Judge Brett Kavanaugh!" the President tweeted, moments after the final tally became official.

Ford's lawyers said their client was not watching the vote unfold on television.

There remains uncertainty about the timing of the final vote, since Montana Republican Sen. Steve Daines plans to walk his daughter down the aisle at her wedding on Saturday.

Daines, however, said he had arranged transportation and could get back to Washington after the nuptials to vote.

"At the end of this weekend, I'll have walked my daughter down the aisle at her wedding and there will be a new Supreme Court justice," he said.

Friday's vote took place after yet another extraordinary twist in the Kavanaugh confirmation process, when the nominee penned a last minute Wall Street Journal op-ed that was seen as an effort to put to rest questions about his temperament.

"I was very emotional last Thursday, more so than I have ever been," Kavanaugh wrote in the Journal. "I might have been too emotional at times. I know that my tone was sharp, and I said a few things I should not have said. I hope everyone can understand that I was there as a son, husband and dad. I testified with five people foremost in my mind: my mom, my dad, my wife, and most of all my daughters."