The BB&T Atlanta Open is a home away from home for Marcos. On Tuesday, he scored yet another win at the ATP World Tour 250 event.
Marcos defeated Aussie qualifier Alex Bolt 6-4, 6-1 in just 59 minutes to advance to the second round. He fired six aces and dropped only seven of 39 service points.
Marcos, who reached his 12th tour-level final in Atlanta in 2015, improved to 5-2 at the hard-court event. He will next face fifth seed Frances Tiafoe with a spot in the quarter-finals on the line. It is their first encounter.
Marcos will hope a return to his favoured surface will provide the summer spark. His last quarter-final appearance came in his last hard-court event in St. Brieuc, France in March.