[reprinting a post from yesterday's GDT, now altered to reflect last night's win]
Last series win over Braves: 24th/25th/26th September 2010 at Nats Park - scores W 8-3, L 0-5, W 4-2; pitchers-of-record Zimmermann, Maya, Burnett respectively.
Last series win at Atlanta: 13th/14th/15th September 2010 - scores L 0-4, W 6-0, W 4-2; pitchers-of-record Maya, Hernandez, Lannan respectively.
Last series sweep by Nationals: 1st/2nd/3rd/4th October 2009 at Atlanta - scores 2-1, 6-3, 6-4 (11), 2-1 (15); winning pitchers Clippard, Hernandez, Segovia, Kensing respectively (in the case of the last two named, these would be their only wins ever as Nationals; in Segovia's case, his only win ever in the majors).