Delaware Attorney General Beau Biden (D) said Tuesday that he is not kicking himself over turning down a chance to run for his father's old Senate seat.

Biden, the son of Vice President Joe Biden, in January decided not to enter the race, instead opting to run for reelection as attorney general. His decision helped turn the open Delaware seat into a prime pickup opportunity for Republicans.

But Christine O'Donnell's stunning victory over centrist Rep. Mike Castle in the state's Senate GOP primary has shifted the race in favor of Democratic nominee Chris Coons, according to recent polls.

Asked by CNN's John King if the state of the race now makes him "kick himself," Biden said "No, not at all."

In an interview to air Tuesday evening, Biden said that he felt the need to get more done at the state's top law enforcement official.

"This is Delaware's seat. I had gotten off a plane from Iraq and then I got put in my lap a really, really critically important case that we're prosecuting in our state. I only had one choice to make and that's to finish my job as Attorney General and that's what I did," he said. "I'm not kicking myself.  I'm trying to go out there and stir it up and do everything I can to make sure Chris Coons, who is our candidate becomes the next U.S. senator. With hard work, I anticipate he will be. He's going to hit the ground running as a senator."

The younger Biden, who suffered a mild stroke in May, said that he is "doing great" and has been "back to work full speed since earlier in the summer."