Marcos enjoyed a strong week at the Open de Rennes, an ATP Challenger Tour event, reaching his first quarterfinal of the 2019 season.
On Friday, Marcos fell to home hope Antoine Hoang 2-6, 7-6(5), 6-4, after registering back-to-back victories over Norbert Gombos and Sergiy Stakhovsky. He held an early break advantage at 2-0 in the third set against Hoang, but could not sustain the momentum. He eventually fell after two hours and 24 minutes.
Marcos entered Rennes on the heels of season-opening tournaments at the Qatar ExxonMobil Open in Doha and Australian Open. He kicked off the year with a win over Lukas Rosol in Doha qualifying, before enduring a pair of tight three-set losses.
Marcos will next head to nearby Montpellier for an ATP Tour 250 event, the Open Sud de France. He is making his second appearance, having reached the quarterfinals in 2016.