Mbappe lit up the start of the knockout stages of the European competition with a hat-trick for Paris Saint-Germain against Madrid's domestic rival Barcelona on Wednesday (AEDT), helping the French club record an outstanding 4-1 triumph at Camp Nou.
Just 24 hours later, Haaland continued his astonishing scoring exploits in the UEFA Champions League, becoming the fastest player to reach 10 goals for one club as he struck twice for Borussia Dortmund in a 3-2 victory away to Sevilla in the Round of 16.
Both young forwards have been rumoured as transfer targets for Madrid, so it was hardly surprising they were a topic of discussion for Zidane during his pre-match media conference ahead of Sunday's (AEDT) LaLiga trip to Real Valladolid.
Asked for his assessment of fellow Frenchman Mbappe, he replied: "I think the performance he put in earlier this week was marvellous.
"I loved seeing what he did because we know each other from France.
"It's very good for football, I watched the game as a fan. I had a very good time watching it. He has a lot of good movement, a lot of good play."
French media has claimed Mbappe has been offered a new long-term deal to remain at PSG.
The 22-year-old's current contract runs until 2022, which is the same year Haaland can leave Dortmund for €75 million ($119 million), according to a reported agreement with the Bundesliga club.
Madrid head coach Zidane, however, was not interested in revealing which of the duo he ranked higher.
"Like I said, what I like is just watching football. I just like watching good football, good players on the pitch," he said.
"Two tremendous players, for now and the future. That's it. I'm not going to say who I prefer over the other. Everyone has their opinion."
The continued rise of Mbappe and Haaland as superstars has led to suggestions they can step in and become the next great pairing, taking over from the longstanding rivalry between Madrid legend Cristiano Ronaldo and Barcelona captain Lionel Messi.
"They are quality players both of them, just like Messi and Cristiano," Zidane said. "Neymar, all these world class players, they're just like them.
"They're younger, they're demonstrating they are not just players for the future but players for the present."