Dan Haren carved up Arizona's lineup and the Washington Nationals blanked the Diamondbacks, 2-0, in the middle test of a three-game set from Chase Field.
Haren (10-14) threw 77 of his 107 pitches for strikes as he went seven innings, allowing just four hits and a walk.
"Haren threw an unbelievable ballgame," Nationals manager Davey Johnson said.
Drew Storen pitched a perfect eighth to preserve the lead and Rafael Soriano earned his 43rd save of the year.
Chad Tracy had a pair of hits, including his fourth home run of the season, in the triumph. Ryan Zimmerman drove in his 18th RBI in September, matching Jayson Werth's team-leading total for the season's final month.
Brandon McCarthy (5-11) pitched well in defeat, serving up five hits and two runs in seven innings.
Both pitchers kept the offenses at bay until the sixth inning, when Washington manufactured a run to take a 1-0 lead. Denard Span led off the frame with a triple to right and Zimmerman followed with an RBI groundout to short.
Tracy's homer in the top of the seventh spotted the Nats a 2-0 advantage.
Soriano ran into some trouble in the ninth when Martin Prado singled and Miguel Montero walked. Tony Campana pinch-ran for Montero and both runners advanced on a wild pitch, but Matt Davidson struck out swinging and Chris Owings flied to left to end the game.
"We had opportunities at the end and weren't able to get it done," D'backs manager Kirk Gibson said.
Both teams hit 0-for-4 with runners in scoring position and stranded seven runners ... Washington outhit Arizona, 6-5 ... Haren threw a first-pitch strike to 20 of 26 batters he faced ... Span's 11th triple of the season moved him into first in the majors in three-baggers.