Cordero walked Eric Byrnes in the ninth and then struck out the side for his 24th save in 27 chances to help Washington beat the Arizona Diamondbacks 4-3, completing a sweep of the day-night doubleheader.
"I haven't done that since, I think, my sophomore year in college, so it's been a long time," Cordero said. "I actually got a loss and a save in the same day. Luckily for me, in the first game I didn't throw that many pitches so I was able to go out there in the second game and give them that one inning. It started off shaky but I was able to finish it out."
Austin Kearns and Ryan Zimmerman homered in the eighth inning of the second game to lead the Nationals over former teammate Livan Hernandez, who tipped his cap to the crowd that gave him a standing ovation as he left the field.
"He deserved the applause and the ovation, there's no doubt about it," Nationals manager Frank Robinson said. "They weren't heckling him like they would do some pitchers from the opposing team. And him being the class guy he is and a real professional, he just acknowledged it, which a lot of players wouldn't do under any circumstances period, but especially under those circumstances. He's a class act."
The Nationals rallied in both games of the doubleheader to extend their winning streak over the Diamondbacks at RFK Stadium to five.
Alfonso Soriano hit a tying two-run homer in the ninth inning of the first game and Zimmerman's bases-loaded walk in the 11th lifted the Nationals to the victory. It was Washington's first back-to-back wins in franchise history when trailing by two or more runs entering the ninth.
Hernandez (10-12) was traded from the Nationals to Arizona on Aug. 7 and took a 3-1 lead into the eighth inning in his return to Washington. He struck out Jose Vidro to begin the inning. After Zimmerman's homer, Nick Johnson singled and Kearns hit a two-run drive to put the Nationals in front.
"They hit good pitches," Hernandez said. "A couple of guys got power. They hit the ball out. You can pitch the whole game perfect and everything can turn around in one inning. I'm not the kind of guy who wants to win because they trade me."
Hernandez dropped to 1-4 since he was acquired by Arizona. He yielded four runs and 11 hits over 7 2/3 innings. He struck out seven, walked one and hit a batter with a pitch. Diamondbacks manager Bob Melvin had no reservations about leaving him in the game for 125 pitches.
"He threw the ball about as well about as you can throw it," Melvin said. "He was our best guy out there at the time. He felt good. He threw one bad pitch. ... He felt great. He knows these guys. He's throwing the ball well the whole game. I'd do it again."
Saul Rivera (2-0) got the win in the second game.
Luis Gonzalez gave the Diamondbacks a 3-0 lead in the nightcap with a two-run homer off starter Jason Bergmann in the third inning after Orlando Hudson reached on a walk.