Marcos' quest for the 300th match win of his career will wait another week, as he was defeated 6-2, 6-4 by Italy's Marco Cecchinato at the BRD Nastase Tiriac Trophy on Tuesday.
Making his third trip to Bucharest, Marcos dropped his first encounter against Cecchinato in 75 minutes, having been broken twice in the opening set and once more in the second. It was his first defeat in an ATP World Tour first-round match in nine tournaments, since Winston-Salem last August.
Two weeks after reaching the quarterfinals on the clay of Houston, Marcos will look to continue his winning ways in Munich, followed by a pair of ATP World Tour Masters 1000 events in Madrid and Rome.
