Nunes was at the heart of the opener, delivering a dangerous cross which was turned into his own net by Marius Hoibraten.
Kovacic netted the second shortly after the interval, claiming his first goal for City.
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Nunes was again involved in the third, as his shot was parried into the path of Bernardo Silva, whose deflected effort found the corner to secure progression into Friday’s final.
“I think he [Nunes] needed this for his confidence and to keep going. He’s a very good player,” said Rodri.
“Very young of course. He provoked the first goal. Mateo Kovacic, he also scored his first goal.
“Both of them are doing very good. We need them. We need them until the end of the season.
“They are going to be important players. I’m very happy for them.
“We need the best of all of us. I hope we give our best in the final.”
The Spaniard spoke about the special feeling of making it through to the final of the competition, touched on how it felt playing in Saudi Arabia and provided his thoughts ahead of the final against Fluminense.
Watch the entire interview via the video at the top of the page.