Is it worth going to the US Open on the first day of the tennis tournament or the previous week of qualifying rounds instead,

Sorry, but what's "worth it" to me may not be worth it to you , and vice versa.

I can't speak for the week of qualifying rounds, but I doubt the atmosphere then would even come close to the excitement and fun of opening week.

If you just want to see some tennis - go to the qualifying rounds and probably pay less. That wouldn't interest me, I'd rather see players I know and am would be willing to pay more to do so.

If you're a big tennis fan (I am), you'd probably enjoy either but I agree with Howard that the first week at the US Open is electric with energy. Lots of fun.

"Electric!" That's the word I was looking for. Thanks, obxgirl.

The qualifiers are a bunch of stiffs who virtually no one knows and who do not matter in the progression of the tournament. Do you want to see Nadal, Federer, S. Williams, V. Williams, Sharapova, et al.? If yes, then you go during the first week, not the qualifiers because the top players have long since qualified.

And the best atmosphere is the night tennis sessions (which used to be a separate ticket and probably still is). There is reportedly a baseball team that plays near the Tennis Center, so you could conceivably watch both sports, but that NYC-based baseball team is not the Yankees, so the quality will be far inferior to what you would see in the Bronx.

Yes, the evening session is a separate ticket.

First day is exciting.

First week day sessions are fun, you get to see really good players up close, since most day sessions seats, are "first come first serve" except for Arthur Ashe stadium and some seats in Louis Armstrong stadium. The ground pass will let you see a lot of tennis during the first 8 days.

Also remember to check out the practice courts, you may catch some of the best players warming up.

Night sessions at Arthur Ashe are great too, if you can get good seats.

Qualifying tournament is free.