Washington (CNN) Vice President Joe Biden says that had he run for president, he would have defeated Democratic standard-bearer Hillary Clinton in the primaries.

"I thought I could beat Hillary. I thought I could beat anybody that ran," Biden said in an interview with CNN's Michael Smerconish that aired Saturday. "No one should run for president unless they think they can do that."

Biden announced his decision not to run alongside President Barack Obama and his wife, Jill Biden, during a press conference in the Rose Garden of the White House last October, ending widespread speculation about the former senator's political future.

Biden has repeatedly said the decision not to run was solely based on the death of his son , Beau Biden, last year.

"I didn't run -- not run -- because Hillary was running. I didn't run because my son's not here. Period," Biden told Smerconish.

Questions regarding Biden's decision not to run come amid a tightening race between Clinton and Republican presidential nominee Donald Trump. With just 10 days ahead of Election Day, both candidates have faced scrutiny and are widely unpopular.

On Friday, Clinton's email controversy was brought back into the spotlight when FBI Director James Comey announced new emails had been recovered that were related to her use of a private email server.

The newly discovered emails are part of an investigation into Anthony Weiner, according to law enforcement sources. Weiner, the disgraced former congressman, recently separated from top Clinton aide Huma Abedin after a sexting incident.

Biden has said before he regrets not running for president.

"I regret it every day, but it was the right decision for my family and for me. And I plan on staying deeply involved," Biden said in an interview with Connecticut NBC affiliate WVIT in January.

Speaking with Smerconish, Biden reiterated his support of the Democratic nominee.

"I have great respect for Hillary," Biden said.