Valencia were outstanding throughout their clash with La Liga leaders Real at Mestalla, and thoroughly deserved their 2-1 victory.
Cristiano Ronaldo gave Real an early lead with a controversial penalty, but Nuno's side kept to their game plan of high-tempo, intense pressing across the pitch and were rewarded with goals from Antonio Barragan and Nicolas Otamendi after half-time.
The win moved Valencia up to fourth and was the ideal way for them to begin 2015.
But, despite being full of praise for his side's performance, Nuno feels the best is yet to come from his players.
"This victory deserves a lot of credit, as does the fact we came vack from behind," the Portuguese told his post-match media briefing.
"However, I still believe that our biggest success is yet to come - it was a great win, but we still only have 34 points.
"It is not the time to celebrate anything, although of course the fans have to enjoy the victory."
Nuno was also delighted with the showing of debutant Enzo Perez, who signed from Benfica for a reported €25million and was excellent alongside Andre Gomes and Dani Parejo in a midfield three.
"Enzo had a very good game," he added.
"He balanced things out constantly, which is necessary when you play with a line of three - it was a great game from him."
