WIMBLEDON, England—After a stop by Aorangi Park, where the majority of practice sessions at Wimbledon take place, yielded only sights of Jerzy Janowicz, Michael Russell (with new coach Peter Lundgren), Victoria Azarenka, and the shoe-borrowing, recently defeated Redfoo, I continued my morning walk around the bustling grounds, with Day 1 minutes from commencement.

Once I spotted a throng of onlookers and a seemingly greater number of iPhones and iPads recording what was taking place on Court 11, I knew I'd found what I was looking for.

It was on this outside court that Rafael Nadal was placed for his hit with good friend Juan Monaco; Rafa will play on No. 1 Court in perhaps three hours, so the two-time champion is getting his fill of how the other half plays today. All the better for those admiring on the sidelines, witnessing a bulked-up version of a pre-match warm-up. There was a spirited, crisp exchange of volleys—even Uncle Toni got in on the act when he was about to be struck by a wayward Monaco shot. There were serves puncturing the verdant lawn for the first time. And there were rallies that, if not emphasizing the side-to-side movement which Nadal excels at, highlighted the north-to-south, stroke against stroke combat which, again, Nadal excels at.

Watching Nadal strike a forehand winner up close, hearing it move through the cool air, and seeing its impact on the Slazenger-sponsored wall behind Monaco, is a sight in itself. But I was most impressed with some of the mini-games these two buds decided to engage in. An all-slice exchange, which usually draws laughs after four or five shots in match play, was played out in silence here; it was a smart drill, considering the low-bouncing surface both men will ply their trade on this fortnight. Nadal's backhand slice has become an increasingly important part of his game over the years, and, like most everything he's done so far this season, it looked in vintage form today.

Next, Nadal asked Monaco to target his backhand, and the Argentine responded in kind. A player who can wear nearly anyone down with his relentless, accurate groundstrokes, Monaco was as reliable as a ball machine, and Nadal worked hard to keep up. Pushed wider and wider, Nadal was forced to try a lunging, stab lob with his final backhand—which naturally sailed over Monaco and fell in. "That'll show him!", an onlooker shouted with applause.

Of course, after the players switched ends about a minute later, the same gentleman asked, "Does anyone know who this is?" Just the world No. 20; no wonder he referred to Monaco as "him."

The remark was emblematic of the opening day, a day you'll hear that question will asked countless times on the many side courts at the All England Club, where play has already begun. Perhaps even on No. 1 Court, where Nadal will face journeyman Steve Darcis. And although Rafa still had hours to recover from a practice that was hardly taxing, I wondered if he was being too strenuous considering today's schedule. Apparently not, as Victor Hanescu, who plays Roger Federer on Centre Court in 90 minutes, was eagerly waiting for Nadal's session to end.