It's how you have to manage the situation. The Nationals could only win that game in two ways (really one but the difference matters) - scoring >3 runs in an inning or scoring 1-3 runs in an inning. The scenario where they score 1-3 runs is much, much more likely so that is going to require a save. If you pitch Doolittle in the 9th then you have to put either Romero or Perez in the even higher leverage situation that a save situation presents.
Tied in the bottom of the ninth is less pressure than up one or more runs in the bottom of the tenth?
No...
