In the same game that brought you this bibelot, Mariano Rivera entered the ninth inning with the Yankees up one run. He retired the Orioles 1-2-3. He did not get the save—but he did get a win. Huh?
With the Yankees up 5-2 heading to the home half of the eight, setup man David Robertson came on and allowed three runs before finishing up the inning. In the top of the ninth, the Yankees re-took the lead, and Rivera came on in the bottom half to seal the win.
Since Robertson was the pitcher of record when the Yankees scored the go-ahead run, you'd expect him get the W and Rivera the save—but that's not actually what the rules say.
10.17(c) The official scorer shall not credit as the winning pitcher a relief pitcher who is ineffective in a brief appearance, when at least one succeeding relief pitcher pitches effectively in helping his team maintain its lead. In such a case, the official scorer shall credit as the winning pitcher the succeeding relief pitcher who was most effective, in the judgment of the official scorer.
Since Robertson gave up three runs in one inning, the official scorer decided he wasn't worthy of the win. So it had to go to Rivera—who, it should be noted, has an incentive-laden contract that likely rewards saves but not wins.
This is perhaps the best single condemnation of the win: How valid can a statistic be when it's often a judgment call?