Marcos is back in Chengdu for the second year in a row, as the ATP World Tour's Asian swing begins this week in China.
After a second round finish last year, Marcos will open against Canada's Vasek Pospisil on Tuesday. He owns a 3-1 head-to-head advantage, with their most recent meetings having come in Dubai and Cincinnati last year. Marcos did not drop a set in either encounter.
Victory over Pospisil would see Marcos face either eighth seed Leonardo Mayer or Peter Gojowczyk. Gojowczyk won his first ATP World Tour title on Sunday in Metz, France. Top seed Dominic Thiem and fourth seed Andrey Rublev are also in Marcos' half of the draw.
Marcos has fond memories of the Asian swing, having claimed his maiden ATP crown in Beijing in 2006. He also reached the final in Kuala Lumpur in 2011.