I think we were looking in that very moment at players that were not in a tournament or who have just lost at a tournament.
Organisers caused controversy earlier this week when the hiked up ticket prices to see Federer play, which many labelled a "rip-off".
The 20-time Grand Slam victor had reached the finals of Italian Open in 2003, 2006, 2013 and 2015. They are unhappy with the Italian Tennis Federation's decision to double prices after Federer was announced.
Federer could come up against eight-time champion Rafael Nadal in the semi-finals in Rome, and Madrid Open victor and eighth seed Stefanos Tsitsipas in the quarter-finals.
However the dual ATP-WTA clay showpiece will restart at on Thursday, after a frustrating day that saw starting times regularly delayed until play was officially abandoned.
"I think it's going to be a good season". I'm happy also that the decision I took last, I guess around December, when I started feeling like I definitely want to do the clay, that it was the right decision, you know, because I haven't looked back at the clay-court build-up yet, or everything that I have been doing, like maybe I shouldn't have. "My excitement couldn't be bigger".
His only Roland-Garros title came a decade ago when he beat Swede Robin Soderling in straight sets.
On Tuesday, rain interrupted the match between defending champion Elina Svitolina of Ukraine and the Belarusian Victoria Azarenka several times.
Chinese 15th seed Wang Qiang also fell to Czech Katerina Siniakova 1-6, 7-5, 6-4.