Third seed Milos Raonic pulled away late to claim a tight third-round encounter over Marcos at the Citi Open. Raonic won their fourth head-to-head meeting 7-6(7), 6-3 in one hour and 32 minutes, striking 16 aces to advance on Thursday.
Marcos put up a fight, impressively turning aside six break points in the eighth game of the opening set. He battled into a tie-break and even earned a pair of set points at 6-4, but was unable to close out the opener. Raonic would claim the first set and broke twice in the second to take the match.
Marcos will leave Washington with his head high after winning his first matches of the North American hard-court season, including a straight-set victory over 16th-seed Ryan Harrison. He will next play in a pair of ATP World Tour Masters 1000 events - the Rogers Cup in Montreal and Western & Southern Open in Cincinnati.