Rafael Nadal clinched the coveted year-end No. 1 ranking for 2013 today with a workmanlike, 7-6 (5), 7-6 (6) win over Stanislas Wawrinka.

This was a match containing numerous “glass half-full, glass half-empty” elements. For while the glory and importance of what Nadal accomplished is obvious, it’s also true that the match could be read as a thesis on what Nadal does wrong, or fails to do right, when it comes to playing on an indoor hard court.

And from the loser’s point of view, Wawrinka, now 1-1, will prepare for his final match of the round-robin stage knowing that he did many things right and was awarded numerous opportunities, most of which he allowed to slip through his fingers.

From the start, one of the main questions was: Could Wawrinka somehow get the monkey of that 0-9 record (in head-to-head matches) and 0-24 record (in head-to-head sets) against Nadal off his back? After all, this is the year when Wawrinka, out from under the shadow of fellow Swiss Roger Federer at long last, has made his strongest move to break through to the elite level where the likes of Federer and Nadal are entrenched.

In the first few games, it was obvious that Nadal’s ball wasn’t going through the court very well, and that he seemed resolved to playing from a defensive posture—willing to chase down anything, as always, yet curiously unwilling, or unable, to press the attack and pressure his opponent. Nadal was unable to capitalize on Wawrinka’s equally defensive posture, or hit with enough precision to run him ragged.

It was Nadal’s good fortune that Wawrinka insisted on playing from well behind the baseline—thereby diminishing his own ability to control the points—and also played it overly safe during Nadal’s service games. Wawrinka often settled for merely getting the serve back in play, often with chip or blocked returns, instead of seizing the initiative on a day when it beckoned.

Nadal had the first break opportunity, in the fifth game. Wawrinka, trying to do a little too much with his forehand, fell behind 15-40. He delivered an ace to brush aside the first break point but then double faulted to give up the game for 2-3.

Nadal played conservative, defensive tennis over the ensuing games. Each player had at least one break point that he failed to capitalize on, but Nadal clung to his lead and served for the set at 5-4. Nadal made two groundstroke errors to 30-all in that 10th game, and then made a curious tactical choice: He hammered away at Wawrinka’s rock-solid one-handed backhand (I guess Nadal mistook him for the other Swiss guy). He then paid a price—a prodigious backhand winner earned Wawrinka break point. Wawrinka then clinched the game with a forehand approach winner, and served an 81-second game to put the heat on Nadal. But Nadal held firm and reached the haven of the tiebreaker.

Wawrinka lost the first point of the breaker, but quickly earned back the mini-break. The points then went on serve until the decisive one, with Wawrinka serving at 5-6. Wawrinka whacked an outstanding approach shot, but stumbled on his way to the net and misplayed the easy volley that Nadal then tracked and converted into a passing shot.

The set was gone; Wawrinka destroyed a racquet on the courtside signage. Just to give you a good idea of who was in control, Wawrinka had 15 winners in the first set—more than twice as many as Nadal.

Nadal continued to play it safe in the second set. He managed to hold a long first game and fend off two break points in the third game. Then he broke Wawrinka in the fourth game, through no heroic actions of his own. The wheels just fell off Wawrinka’s game as he made three cringe-worthy errors to fall behind love-40. Nadal then pitched in a bad error of his own, but was obliged to win the game when Wawrinka hit an inside-out forehand beyond the sideline. That left Nadal in charge, 3-1.

But the blurry nature of Nadal’s game gave Wawrinka plenty of chances to score with those big, roundhouse swings. He did so in the seventh game, when he jumped ahead in Nadal’s service game, 15-40, and broke when his rally-ending forehand volley skipped off the let cord and fell for a winner.

By that point, Nadal was putting barely half of his first serves into play and Wawrinka was doing even worse. The men battled on through unpredictable games, but nobody was broken the rest of the way.

In the tiebreaker, Nadal held and scored two quick mini-breaks. But over time he surrendered the sizable advantage and the men were dead even at 5-5, with Wawrinka serving one more point. He held, giving him a set point, but Nadal also held his two serves to take a 7-6 lead—match point. The top seed ended it when he poked a return back into play and Wawrinka drilled a final forehand into the net.

Nadal probably will need to play better if he hopes to finally win the World Tour Finals, and with the year-end ranking issue resolved, perhaps he’ll play with a little more of the aggression that he needs but currently lacks.