Hillary Clinton had more than just her birthday to celebrate on Monday. As October draws to a close, Clinton and her campaign are raising a glass to what they call an "incredible" month in the long race to the White House.

A sense of relief is likely being felt at her 2016 presidential nomination headquarters in Brooklyn, after a rough summer when Clinton's poll numbers dipped and she struggled to get positive press attention. 

The personal email server controversy dragged her down, and at the same time her top rival Bernie Sanders was drawing ever larger crowds. The Vermont senator stole the spotlight from Clinton, and she needed to get it back and get some momentum on her side.

It appears she has done just that, thanks to some strategic moves by her campaign and to a string of events that worked in Clinton's favour. When the race is finally over, whichever way it goes for Clinton, October could be looked upon as a point in her campaign when things changed for the front-runner.

"I think the past three weeks have been the best three weeks of the campaign," Democratic strategist and political commentator Maria Cardona, a Clinton supporter, said in an interview. Cardona said there is "no question" that Democrats who had doubts about Clinton's potential as a candidate have been reassured.

"This string of events that have happened in the past three weeks have really made Democrats a lot more comfortable, some of them even giddy, about her possibility," Cardona said.

'Benghazi gift'

Cardona thinks the tide started turning for Clinton when her campaign made the decision to have her apologize for using a personal email server when she was secretary of state, a decision that has caused the FBI to look into whether any classified information was put at risk. Cardona said Clinton's apology in early September helped change the tone of her campaign.

A few weeks after that, Republican House majority leader Kevin McCarthy gave Clinton what's being called "the Benghazi gift." A special committee on Capitol Hill has been investigating for 17 months what unfolded in Benghazi, Libya, on the night of Sept.11, 2012, when a U.S. compound was attacked and four Americans, including ambassador Chris Stevens, were killed. Clinton was secretary of state at the time and some Republicans accuse her and the Obama administration of mishandling the incident and of misleading Americans about what really happened.

In a TV interview at the end of September, McCarthy said this: "Everybody thought that Hillary Clinton was unbeatable, right? But we put together a Benghazi special committee, a select committee. What are her numbers today? Her numbers are dropping."

Democrats were delighted to hear a top Republican say that. It bolstered their case that all along the Benghazi committee has been more about discrediting Clinton than about getting the facts.

With that lift to her campaign, Clinton headed into October with some high-stakes events ahead of her: the first Democratic debate and her appearance at the Benghazi committee.

DEM 2016 Biden

Vice-President Joe Biden announced on Oct. 21 that he would not challenge Hillary Clinton for the nomination, removing one more obstacle on her path toward the White House. (Jacquelyn Martin/Associated Press)

There was plenty of pressure to perform well on Clinton when she, Sanders and the three other candidates vying for the nomination gathered on stage in Las Vegas for the debate on Oct. 13. (Two of them have since dropped out.)

Clinton rose to the occasion and skilfully handled tough questions and confidently made her case for why she believes she is the best candidate to win the White House.

Clinton was equally calm under pressure when she endured 11 hours of questioning at the Benghazi hearing on Oct. 22. Republicans did not manage to get under her skin nor did the marathon questioning produce any smoking guns or bad press for Clinton.

Joe Biden's boost 

Peter Fenn, a Washington-based political commentator and Clinton supporter, said Clinton's performances at the debate and then the hearing were "extremely helpful to her."

Fenn said Democrats who were on the fence about Clinton came over to her side in October. "The fact that she seems to be the adult in the room and excelled in those situations gives people the added confidence that she would be a very good president," Fenn said in an interview.

The saying "when the going gets tough, the tough get going," aptly applies to Clinton, he said. "When the chips are down, she tends to shine."

The other event that worked in Clinton's favour was Vice-President Joe Biden's announcement — the day before her Benghazi testimony — that he would not join the race. That was also helpful to Clinton, whose campaign now has one less challenge to deal with on the road to the nomination.

Cardona said the campaign saw the debate and testimony as critical opportunities to change the dynamic of the race and they succeeded in taking advantage of them.

"They were pivotal," she said.

Now the next challenge is to maintain the momentum Clinton built over the last month. Clinton's campaign manager Robby Mook described October as an "incredible month" that should be celebrated, in a note to supporters, but he also warned, "it's important not to get complacent during good times, just as it's important not to panic during challenging ones."