The fourth-seeded Argentine encountered few problems against the Slovenian qualifier and will now meet Brazil's Joao Souza in the last eight.
Souza was leading wildcard Dusan Lajovic 4-2 when the home player retired with a twisted right ankle.
Second seed Andreas Seppi also cruised through, the Italian seeing off Croatian Ivan Dodig 6-4 6-2 after converting five of his seven break point opportunities.
Seppi goes on to face Gilles Muller in the quarters after the player from Luxembourg beat Eduardo Schwank 6-3 7-6(0).
Muller's serve proved too powerful for his Argentine opponent, who saw eight aces flash past him during the match.