Marcos improved to a perfect 16-0 record on the ATP Challenger Tour this season as he reached the second round of the Napa Valley Challenger on Tuesday with a 6-3, 6-2 victory over American wild card Marcos Giron.
Marcos wrapped up the first-round win in 84 minutes, saving five of the six break points he faced and breaking the No. 474-ranked Giron four times.
For a place in the quarter-finals, Marcos will face John Millman, who won an all-Australian clash with Matt Reid 6-1, 6-2.
Marcos is bidding to win his fourth ATP Challenger Tour title of the year, adding to victories in Nottingham, Aptos and Vancouver.
