Justin Gimelstob played in his first U.S. Open in 1995 at age 18, advancing to the second round before losing to Richard Krajicek. AP

Outspoken tennis pro Justin Gimelstob is writing every few days during the U.S. Open, where he competed in the men's singles, men's doubles and mixed-doubles competition. Click here to read all of Justin's entries.

I just finished my 11th U.S. Open as a professional and, after the way I played, I'm definitely feeling the effects of how challenging, isolating and frustrating this great sport can be.

And while I'm pretty sure you don't want to read another "professional athletes have it so tough" column, I do want to make it clear that it isn't all about the finals on prime time next weekend, the private jets or five-star hotels.

I'm very fortunate to play professional tennis for a living. Tennis has enabled me to travel the world, meet incredible people and compete in the most prestigious tournaments, measuring myself against the game's best. I have had the unique opportunity to find something I truly love. For this I am very thankful, but it has come at a great cost, both physically and emotionally.

For me, the U.S. Open is the most important event of the year. My childhood dreams were of winning it, and my family and I went there every year from the time I was 8 years old. My brothers and I witnessed some incredible matches, including Brad Gilbert upsetting Boris Becker in 1987, followed by Ivan Lendl beating Mats Wilander in a hard-fought final, and the famous Jimmy Connors/Aaron Krickstein marathon in 1991. It was those early experiences that made me decide that I wanted -- and would sacrifice everything I could -- to become a professional tennis player.

Things went according to plan. I was a successful junior tennis player, and in 1995, by virtue of winning the National Boys 18's Championships, I received an automatic berth into the U.S. Open.

My first match played out like a fairy tale. I beat a solid professional, David Prinosil, in a five-set thriller before bowing out to the accomplished Richard Krajicek. But I was back at the Open over the next 10 years, netting some great memories, as well as some understandable disappointments -- the highlight being a tough four-set loss to eventual champion Andre Agassi in the third round in 1999.