WASHINGTON – Chicago second baseman Neifi Perez’s two errors helped Washington score the go-ahead run in the sixth, and Nick Johnson hit a two-run homer to lead the Nationals past the Chicago Cubs 5-4 on a rainy Sunday.

After his 2004 Montreal Expos went 16-30 in one-run games, Washington manager Frank Robinson said all spring that the Nationals’ success this season would depend greatly on how they fared in such contests.

Well, they’re getting plenty of practice lately, including in six of the past seven games.

Johnson’s homer came in the fifth off Greg Maddux, who walked the preceding batter, Jose Guillen, and complained about the landing area on the pitcher’s mound. The RFK Stadium mound has drawn criticism much of the season and was rebuilt last week while the Nationals were away.

It was Johnson’s fifth homer and put Washington ahead 4-3. That was the last inning for Maddux, who allowed four runs and seven hits.

The Cubs tied it at 4 in the sixth, when Jeromy Burnitz walked, advanced on a groundout, and came home on Jason Dubois’ double. After Ronny Cedeno singled and pinch-hitter Ben Grieve walked to load the bases, Nationals starter John Patterson was lifted. He allowing four runs and seven hits in 5 2-3 innings.

Hector Carrasco (1-0) got Corey Patterson to pop out on his only pitch and earned his first win since Sept. 4, 2003, with Baltimore. Luis Ayala pitched two innings for Washington – benefiting from Guillen’s crashing-against-the-wall catch on Derrek Lee’s fly in the seventh. Chad Cordero worked the ninth for his ninth save.

In the past week, Washington has gone 3-3 in one-run games, and is 6-5 overall.

In the sixth, with Chicago’s Cliff Bartosh (0-2) on the mound, Ryan Church reached when Perez bobbled the ball. Brian Schneider sacrificed him to second. Cristian Guzman then hit another grounder to Perez, who didn’t get his glove all the way down, allowing the ball to roll underneath and ricochet off his left ankle for another error.

Church easily beat the throw home from shortstop Ronny Cedeno.

Rain delayed the start of Saturday night’s game by 2 hours, 40 minutes, and drops started falling in the fourth inning Sunday. Wet grass and a slick ball might have contributed to Perez’s miscues – and to errors by Patterson and Cubs catcher Michael Barrett.

In the fifth, Maddux went to a 3-2 count on Brad Wilkerson and threw his arms in the air, then kicked at the dirt on the mound. Two batters later, he called out the plate umpire, and three grounds crew workers added some dirt.

After a two-minute delay, Maddux walked Guillen on four pitches, went to 3-0 on Johnson and, after a called strike, gave up the homer into the box seats just below the upper deck in right-center.

Before the top of the sixth, there was a three-minute delay while more work was done on the mound at Patterson’s request. He was undone by walks as three of the four scored.

Notes: The Nationals put INF Henry Mateo back on the 15-day disabled list with right shoulder tendinitis, making room for OF Marlon Byrd, acquired from Philadelphia on Saturday. … Cubs 3B Aramis Ramirez sat out with tightness in his back, the same problem that held him out Wednesday. Burnitz took his cleanup spot, and Jose Macias replaced Ramirez at third. … RHP Carlos Zambrano will return to Chicago on Monday for tests. He left Saturday’s game in the fourth inning with tightness in his right forearm. … About two hours before the game, Cubs RHP Kerry Wood (DL, strained right shoulder) leaned back on a chair in the visiting clubhouse and broke it, drawing guffaws from teammates. Wood, who wasn’t hurt, stood up and declared that perhaps it’s time for him to switch to egg whites.

AP-ES-05-15-05 1559EDT