Arguably the pick of the opening-round fixtures comes in Sochi on Friday evening as the Iberian rivals face off with Group B points on the line.
Nacho highlighted his versatility in Spain's friendly win against Tunisia on Saturday by filling in on the left flank, and he now hopes to be handed a starting spot for La Roja's massive showdown with Portugal in five days' time.
"I hope that I have the chance to play against Cristiano Ronaldo, we must be focused on cancelling him out," he told reporters. "The coach knows that I'm qualified to start in this position, I'm prepared.
"Everyone knows that I feel more comfortable in the centre than at full back, but I've played big matches there."
Spain also face Iran and Morocco, on June 20 and June 25 respectively, for a place in the last 16.