Lorenzo Insigne had put Napoli ahead with a spectacular eighth-minute strike, but Real were level just 10 minutes later thanks to a goal from Karim Benzema, before Toni Kroos and Casemiro scored in the second half to give Madrid the advantage.
Speaking to UEFA.com, Zidane said: "We played a great game – it was a shame about the Napoli goal but we rectified things, scored ourselves and turned the game on its head and I think it was the right result.
"We'll go [to Italy] to a difficult ground where we'll suffer and it is still an open game. We need to go there and finish it off with our 3-1 advantage."
— FOX Sports Asia (@FOXSportsAsia) February 15, 2017
Zidane also spoke highly of Kroos after his goal early in the second period put helped Madrid get their noses in front.
"Kroos likes to arrive late in the box and we spoke about it recently. He has the capacity to run more both defensively and attacking,” said Zidane.
"He has brilliant feet and can score from those kind of positions and I'm very pleased for him."
— Real Madrid C.F. (@realmadriden) February 15, 2017
Napoli coach Maurizio Sarri was disappointed, and said that mistakes had cost his side, but added that his side would do their best to make the second leg competitive.
"We faced the best team in the world but it is a pity that we made so many mistakes with the ball because we don't usually do that,” he said.
"Playing in such a stadium against such a team can be very challenging for young players but this is the way you grow as a player.
"While we were not at our best tonight I think we can compete with them if we play our best football. We have only a small chance now but we will try to give everything and see what happens."