Marcos advanced to the quarterfinals at the Hall of Fame Tennis Championships in Newport, downing qualifier and home hope Brian Baker 6-4, 6-3. It is Marcos' debut appearance at the ATP World Tour 250 event.
Marcos, who prevailed in 65 minutes, advanced to his third grass-court quarterfinal of the season. He fired six aces and did not face a break point, while claiming an impressive 90 per cent of first serve points.
"The conditions were tough today," Marcos said. "It was tough to feel the ball and play good tennis, but I'm happy the way I returned serve and happy to get the win."
Seeded fourth this week, Marcos broke in the third game of the opening set and notched the decisive break in the fifth game of the second. He would secure the win on his first match point, breaking once again.
Baker owned a 2-1 record over Marcos in their junior days, but Marcos turned the tables in their first pro encounter on Wednesday. He will next face another 31-year-old in Dudi Sela for a spot in the semis. Marcos won their lone ATP World Tour meeting in Delray Beach in 2009. The match will be third on Stadium court on Thursday.
Meanwhile, Marcos' doubles bid alongside Gilles Muller came to a close. They were beaten by fourth seeds Purav Raja and Divij Sharan 6-4, 6-4.
