Marcos will hold his head high after a strong week at the Chengdu Open, but his run came to an emotional end on Sunday after retiring in the final.
Facing Denis Istomin with the title on the line, Marcos was forced to stop playing in the sixth game of the first set with a back injury. He admits that the back spasms began after Saturday's semifinal victory over Guido Pella.
"I was feeling a bit of pain in my back during the week, but late after my match last night I felt some spasms," Marcos said. "This morning I woke up a bit the same. After my warmup, it got worse. The ATP physio worked on me for an hour and a half. I was okay for three or four games and the spasms came back. I've had back issues before, but not like this.
"It's a bit disappointing to finish this way, but it's true that it's always positive to be in the final of a tournament. I have to thank all the people that made this event possible. They do a great job here. I love this place and I'll hope to come next year too."
It was an impressive week for Marcos as a whole, having rallied from a set down in three matches. He reached his first final of the season and 14th of his career, and is poised to return to the Top 100 of the Emirates ATP Rankings on Monday.
