Tennis at the Olympics has always been in a peculiar position. It's a big enough sport with some of the most famous athletes, but with 10+ other sports at the same time, you won't be watching round 1 matches all day. You have to have some legendary matches happening like Federer-Del Potro, Djokovic - Del Potro, or it's the final stages to really get peoples attention. After back-to-back Grand Slams and just a few weeks before another, i don't see how you can devote hours of watching your ordinary Mertens - Pegula matches, when you've seen them all year long.
I honestly think they should have it starting the monday before the Opening Ceremony and have the first 4-5 days only for it (and the usual football). It will fit with the regular tennis calendar and players can go prepare for the US after that and it would be a nice introduction to the competitions and you can still have the medal matches after the Opening Ceremony.