PITTSBURGH (AP) -- Tyler Moore knew what Clint Hurdle was thinking.
With one out and first base open in the eighth inning of a one-run game, Moore fully expected the Pittsburgh Pirates' manager to intentionally walk the batter in front of him. Moore was hitting .158 and had struck out six times in the three-game series.
''It fires you up,'' Moore said. ''I would have done the same thing.''
The move backfired, though, as Moore followed the walk to Adam LaRoche by hitting a three-run homer off rookie reliever Bryan Morris to seal the Washington Nationals' 6-2 victory over the Pirates on Sunday.
LaRoche had been 4 for 7 with four walks in the series to that point.
''LaRoche had been on base all weekend and seeing the ball well,'' Hurdle said. ''We decided to go right-on-right there with Morris against Moore and it didn't work out.''
Danny Espinosa homered and drove in three runs and Gio Gonzalez (3-2) won for just the third time in seven starts after winning 21 games last season.
Moore homered for the first time this year after hitting 10 in 75 games last season as a rookie. He also hit the go-ahead sacrifice fly Saturday in the ninth inning as the Nationals edged the Pirates 5-4.
''Tyler certainly proved last year that he's a run producer but he's been out of whack this season,'' Washington manager Davey Johnson said. ''Hopefully, this is a good sign that things are starting to turn for him.''
Nationals star Bryce Harper was ejected in the first inning for disputing a checked-swing third strike. He tried to hold up on a 2-2 pitch from Wandy Rodriguez and home plate umpire Bob Davidson pointed to third base ump John Hirschbeck for help. Hirschbeck ruled that Harper had swung.
Harper stood outside the batter's box, stared at Hirschbeck for a few moments and dropped his bat. Hirschbeck then tossed last season's NL Rookie of the Year. It was the first ejection this year for Harper and second of his career.
''I'm not going to badmouth anybody, I'm just happy we got the W,'' Harper said.
Said Johnson: ''John's a good umpire and he made the right call. It's tough losing a player in the first inning, though.''
Starling Marte hit a leadoff homer in the first, his fourth home run in five games for Pittsburgh.
Espinosa's two-run homer in the fourth put Washington ahead for good at 3-1. He also hit a sacrifice fly in the second as the Nationals won for the fourth time in five games.
''I've made some adjustments in the last few days to help me get the bat to the ball quicker,'' said Espinosa, who is hitting just .185. ''I'm feeling a lot better at the plate.''
Gonzalez (3-2) allowed two runs and five hits in six innings, walking two and striking out five. He had been tagged for 18 runs and 21 hits in his previous four starts, going 1-2 in that span.
''Gio did a great job of keeping us in that game after the tough start,'' Johnson said. ''He pitched well.''
After Marte homered, the Pirates loaded the bases in the first with none out. Gonzalez escaped the jam by striking out Russell Martin and Michael McKenry and getting Brandon Inge to ground out.
''The Pirates came out hacking and the game was speeding up,'' Gonzalez said. ''When the game speeds up, you can't get too aggressive and go head-to-head with their aggressiveness. To his credit, (catcher Wilson) Ramos saw that and had me slow the game down and stay calm.''
Ramos had three hits for the Nationals. Roger Bernandina, who took over for Harper after the ejection, had two hits after entering the game with only one hit all season in 25 at-bats.
Rodriguez (2-2) gave up three runs and six hits, striking out seven and walking one in six innings.
The Pirates pulled within 3-2 in the sixth when Martin hit an RBI double.
NOTES: Washington CF Denard Span returned to the lineup after sitting out his first game of the season Saturday with a bruised left foot. ... Nationals RF Jayson Werth, who missed his third straight game with a strained right hamstring but expects to play Tuesday night when Washington hosts Detroit in the opener of a two-game series. Moore subbed for Werth in right for all three games of the series. ... Tests conducted on Pittsburgh RHP Charlie Morton's right arm revealed no structural damage. Morton, who is recovering from Tommy John surgery performed last June, left his rehab start with Triple-A Indianapolis on Friday after three innings with discomfort in his shoulder. He will start playing catch Monday and is tentatively scheduled to throw off a mound during the four-game series against the Mets in New York that begins Thursday. ... The Pirates, like the Nationals, are off Monday then open a two-game home series with Seattle on Tuesday night.