Hanrahan entered in the fourth inning and struck out eight batters in three innings. At one point, he whiffed seven straight batters.
"Now you want to talk to me. You haven't talked to me all spring," Hanrahan joked, setting aside the chocolately treat.
What impressed the Nationals about Hanrahan's outing was that he was able to strike out some of Atlanta's best, including rising star Yunel Escobar and slugger Mark Teixeira.
"It was tremendous. It was a great outing," Nationals manager Manny Acta said. "[I liked the way] he threw the ball. [He had] command of his pitches. The hitters that he did it against, that's what made it a lot better."
Tuesday wasn't the only time Hanrahan has showed he has had the right stuff. He has been doing it all spring, having yet to give up a run in 7 2/3 innings.
But being on the bubble for the 25-man roster, Hanrahan can't afford to do anything less. He is out of Minor League options, so that might help him in his bid to become one of seven Opening Day relievers in the bullpen.
The expections the Nationals had of Hanrahan, 26, might have been uneven entering Spring Training, and for good reason. On Aug. 21 last season, Hanrahan had a respectable 3.42 ERA as a starter. But he ended the season by giving up 23 runs in his last 23 innings.
To make matters worse, Hanrahan would often get two quick outs in those final 23 innings before getting taken out of the game after he had difficulties getting that third out. It seemed he couldn't even get opposing pitchers out.
"I have no idea [why disaster struck]," Hanrahan said. "Maybe with two outs, I would have the mind-set of, 'Throw a strike and get a quick out.' Then when you are trying to do something too much, something bad is going to happen. It was like, 'I don't want to give up a home run here.'"
After the season ended, the team decided he was better off in the bullpen. The feeling was that there would be a lot less pressure on Hanrahan as a reliever.
"He struggled with the pitch count and pacing himself," Acta said "He is better suited to come in for a couple of innings and let it fly. He doesn't have to worry about pitch counts."
Hanrahan, a native of Iowa, took action to better himself this offseason. He asked friend and former Major League pitcher Matt Kinzer to come to Dallas to help refine his skills on the mound. Kinzer taught him how to throw a slider and told Hanrahan he needed to straighten out his stride on the mound.
"He came down and we worked out for about a week together. It took maybe four or five pitches [to throw the slider the right way]," Hanrahan said. "That is what has helped me so far this spring."
Hanrahan said he loves being a reliever. He is more comfortable on the mound and no longer thinking about walking hitters or giving up runs.
"I'm not trying to hit corners. I'm letting it go," Hanrahan said. "I feel being a reliever is working out pretty well. If that's the role I'm going to be in, that's fine. I'm learning the reliever's role in Spring Training -- knowing how many pitches it takes to get ready."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.