The La Liga champions scored all five goals in a scintillating first half as they claimed a win that moves them to within five points of league leaders Barcelona, having played a game more.
Nacho opened the scoring in only the third minute at the Santiago Bernabeu before goals from Toni Kroos, Achraf Hakimi and a Cristiano Ronaldo double put the result beyond doubt before the half-time whistle.
Nacho agrees it was probably Madrid's finest 45 minutes of football in 2017-18 and he hopes the standard is maintained at the Club World Cup next week.
Asked if it was their best half this term, he said, as quoted by AS: "Maybe. We had total dominance of the game in the first 45 minutes. We wanted to keep it going in the second half.
"Just like the other day against Borussia Dortmund [in the Champions League], we spoke about going out strong, to try to dominate. We did that in the best way; the reaction of the team was to fight until the end.
"Sevilla are an amazing team who are always going to be fighting going forward. The objective was to keep a clean sheet and get goals."
Ronaldo showed off his collection of five Ballons d'Or before kick-off, the Portugal star having won his latest individual prize this week, and he delivered an outstanding display that included him winning the ball back in his own half to start the move that ended in Kroos' goal.
"I'm happy for him, hopefully there are many more goals to come, with games like the one today," Nacho said.
Full-back Achraf, whose first goal for Madrid killed off any lingering hope of a comeback for Sevilla, admits it was a proud moment.
"It's a day I won't forget. I'm very happy," said the 19-year-old.
"It's been a year of working, of learning from my team-mates, who are the best. Little by little, I'm going to improve.
"It was a spectacular first half. We went out from the first minute knowing what we had to do."