"I did sort of feel that survivor guilt in 2004, like every time I win a game, it's because I've crushed two other players' dreams," he said. "Playing against Watson ... it really was devoid of that, it could be this killer instinct. I hate this competitor as I have hated no other competitor because ... it has no feelings."
The record-holding "Jeopardy!" winner added that it was nice to be the underdog for a change.
"I got the feeling the first time I was on 'Jeopardy!' that probably, at some point, people were rooting for me to lose, because no one cheers for the Yankees," he said. "And I sort of liked the idea that, this time, presumably everyone except for IBM shareholders is going to be cheering for me and Brad. That was a very good feeling."
Still, Rutter said, those shareholders do have a mighty powerful computer on their side.
"I think humans will be surprised," he told ABCNews.com. "Especially because it's just "Jeopardy!" clues like you see every day on the show. To see a computer actually figuring it out, with all the little twists and turns and puns that they like to get in there, even factoring those in. To see how well Watson is doing, I think might scare some people."
Potentially anticipating the sci-fi-fueled "eventual robot takeover of society," Rutter said IBM has been emphasizing that Watson is an "it" and not a "he."
"I think they sense that people will get freaked out by how well it's doing and how well it can approximate a human," he said.
But regardless of whether Rutter, Jennings or Watson wins the match, Rutter said, no one really loses.
"Ken and I are representing humanity in this thing but, at the same time, Watson was developed, built, programmed by human beings," said Rutter. "So I think humanity wins no matter what happens."
And beyond even that, Jennings said that playing the world's most sophisticated computer gave him a new appreciation for the humble human brain.
"I was impressed at the end that the human brain -- just a few dollars worth of water and salt and protein and whatever else we have in our skulls -- that that could hang in there and play at the same level as this jillion-dollar computer the size of a room," he said. "It says a lot for the human brain that with what we have we can hang with the world's most powerful computer. It's sort of a newfound respect for what our heads can do, which we take for granted sometimes."