It was 1964, Jennings had just joined ABC News and was a back-up correspondent for another reporter. Koppel was with ABC Radio and the two met covering Sen. Barry Goldwater in the presidential race.
With neither of them getting much air time and with Goldwater in seclusion as it became clear he wouldn't win, a young Koppel and Jennings took the sports car on the desert roads behind their hotel, the Camelback Inn, on the last day of the campaign.
Speaking in Toronto as he prepared to honour Jennings with a special tribute at Thursday's Canadian Journalism Foundation gala, Koppel recalled the day he shared with his late friend and declared it one of the best days of their lives.
"There was this snaking road that went up behind the hotel," Koppel said.
"One of us would take our shirt off and stand at the top of the mountain with a stopwatch and wave that shirt then the other guy would come screaming out the hill in this Austin-Healey, as I recall.
"We did that all morning and we swam and played tennis in the afternoon and we went out, had a good dinner. We just had a wonderful time."
Born in Toronto, Jennings worked in radio and at CTV before moving to the United States and went on to report from all over the world and anchor ABC's "World News Tonight."
Jennings' Canadian roots were very important to him, Koppel said, saying he retained much of his Canadian character in his understated manner.
"The Canadian part of Peter would have been acutely embarrassed by all the fuss that's going to be made about him tonight," Koppel said.
"The naturalized American would have relished every moment of it."
The 1964 campaign was the start of a long friendship between Jennings and Koppel, the former anchor of ABC's "Nightline."
Jennings was "devilishly handsome," Koppel said, reminiscing about how his friend was just as legendary with women as he was with the news.
"Sort of James Bond-ish-ly handsome," Koppel described. "Women were definitely attracted to him, yes they were. I noted on the occasion of his memorial service that it is really astonishing given how attractive he was to women that he only married four of them. Peter was a magnet."
It was the only hint Koppel would give about all the other tales he could tell about Jennings. He said he would be keeping those close to his chest.
"Most of the stories that I have about Peter, since I was and am a friend of his, I am not going to share with anyone, thank you very much," Koppel said.
"But he was a dear friend and I loved him very much and miss him a great deal and American journalism certainly does miss him. We could use about half a dozen Peter Jennings today."
Koppel, who after being anchor and managing editor of "Nightline" for 26 years is the longest-serving news anchor in broadcast history, also shared this thoughts on various aspects of the changing news landscape.
On media outlets' growing partisanship:
"I think it is probably the most, or certainly one of the two or three most corrosive factors in the American political process today...I think it's going to get worse before it gets better. I think that when we finally hit the nexus of all these different crises that are coming together whether it's the after-effect of the wars in Iraq and Afghanistan, whether it's the banking crisis, whether it's the unemployment, whether it's the debate over health care, when all of these things come together and nothing effective is done to solve the problems because partisanship won't permit it, then perhaps I think the public will be of a mind to say, 'Something's got to change.' I hope that happens sooner rather than later. I'm not optimistic."
How partisanship and the blurring of the line between opinion and news is changing news from when he started out:
"It's not that we weren't competitive, we were competitive as hell. But we were competitive in trying to get to the most important stories, not competitive in terms of trying to say, 'You're a fascist. You're a communist. You're too far left. You're too far right.'"
Lamenting the trend of media outlets shuttering foreign bureaus:
"(You lose) knowledge, forewarning of serious events. When you only have four or five foreign correspondents you're limited to sending them to places where disaster has already struck — once the revolution happens, once the war breaks out, once the crisis occurs, then you send people in and maybe they'd been to that country before and maybe they hadn't. The advantage of having resident correspondents is that they're the canaries in the coal mine. They let the American or Canadian public know where danger is brewing and where something bad may be about to happen."
On journalism and Twitter
"Social media is clearly here to stay. It's not a question of whether I like it or I don't like it, it's here...I worry about it as a tool of journalism because it is important to know who your journalists are. It's important to know who your reporters are. It's important to know what their biases are. It's important to be able to understand that they operate within a functioning system of journalism where there are editors and producers and/or managements that hold them to account for getting things wrong. When you can just tweet something or put it on your Facebook and say here it is and I have no idea who the tweeter is or who my friend on Facebook is, that becomes a little more dangerous. I worry about that."