Marcos was on the brink of elimination in his second round encounter against France's Paul-Henri Mathieu, but rallied from a set down to advance to the Irving Tennis Classic quarter-finals.
In his fourth head-to-head battle with Mathieu, Marcos prevailed 4-6, 7-6(5), 6-1. He fired nine aces and converted on five of eight break points during the one-hour and 48-minute affair. Marcos moved to 2-2 against the Frenchman and former World No. 12. It was their first meeting in six years.
Marcos will vie for a spot in the Irving semi-finals when he faces Aljaz Bedene on Friday. The match is scheduled for 1:00pm local time on Championship Court.
