This story is part of Peak, The Athletic’s desk covering the mental side of sports. Sign up for Peak’s newsletter here.Jim Courier was the world’s No. 1 ranked tennis player for 58 weeks in 1992 and 1993 and won four Grand Slam titles. He is a tennis analyst for various TV networks.The day I became the No. 1-ranked tennis player in the world was a bittersweet Monday.In tennis, the world rankings don’t change until Monday. That’s when they alter them from the prior week’s results. I knew beforehand that I needed to reach the finals of a tournament in San Francisco to secure the No. 1 spot. I did that by winning the semifinals on Saturday night. I wasn’t officially No. 1 at that point, but I knew I was going to be.I played the final on a Sunday, and I relaxed in a way. Whether it was fatigue or an emotional letdown, I don’t know. But I didn’t play particularly well, and I lost.I had to take a red-eye from San Francisco to New York City, then fly to London and Brussels by Monday night for another tournament. Here’s the funny part: The plane’s nose wheel broke as we were backing out from the gate, so I spent most of my first day as world No. 1 in the lounge at JFK.Getting to No. 1 was a surreal moment for me because it wasn’t something I dreamed of growing up. I wasn’t a “chosen one.” I was a grinder. When I started to climb the mountain in the sport, becoming the No. 1-ranked player was not something that was on my radar. It didn’t seem possible.