McClenaghan recorded the best figures by a New Zealand bowler on debut, returning 4-20 from 10 overs, and it was appropriate the 26-year-old was at the other end when Franklin (47no) hit the boundary which secured victory.
Franklin came to the crease with his team on 81-5 and having as much trouble with the Boland Park wicket as the hosts experienced. The allrounder enjoyed vital partnerships with Nathan McCullum (24) and Kyle Mills (26) before knocking off the 22 runs still required when New Zealand went down to their last wicket.
"It's certainly nice winning, compared to losing," Franklin said. "It's been a hard couple of weeks. We've come up against a very strong South African test side and they're a very good one-day side as well.
"It was extremely hard work out there today, and we're under no illusions that we have to be almost at our best - if not at our best - to compete with these guys and win."
Franklin was initially conservative, taking 25 balls to reach double figures, and thought that approach was needed after watching wickets tumble in both innings.
"We knew we were ahead of the run rate and we knew it was just a case of trying to bat as deep as we could and take the game as deep as we could."
With the fall of Mills' wicket, Franklin immediately upped the tempo and hit 19 from nine balls as New Zealand were on their last life.
"Mitch came out and he had to get through four balls initially and he was resolute in defence," he said. "Then it was just a case of myself being a bit more aggressive and having a bit of a dip, because I knew it was obviously going to be me that would have to get the majority of the runs."
McClenaghan successfully defended six balls to allow Franklin to finish the chase, capping a perfect day for the Auckland left-armer. Having made a delayed start to international cricket, courtesy of injury problems which have resulted in three hip operations, McClenaghan appears ready to further strengthen the Black Caps' already solid seam stocks.
"Mitch has bowled really well in one-day cricket back home, particularly last season," Franklin said. "He's here now seeing where he fits in international cricket.
"For a guy to come in and do that on debut against South Africa in their own backyard is nothing short of outstanding. It's his first outing and I'm sure the South Africans will be busy planning over the next couple days how to counteract him in Kimberley."