WASHINGTON -- In his first two at-bats, Danny Espinosa hit the ball as hard as he had in weeks and all he had to show for it was two more outs.
In his third at-bat, he made a very loud statement that his dreadful slump might be a thing of the past.
The Nationals second baseman drove the first pitch thrown by Pirates reliever Jose Ascanio into the left-field bullpen, scoring Michael Morse, who had singled off hard-luck Pittsburgh starter Paul Maholm (1-6).
"My first thought was I helped the team -- we're leading," Espinosa said. "My second thought was, 'bad idea by [Pittsburgh] to bring in the righty.' "
Espinosa's 22 RBIs lead all rookies, but he has seen his average dip from .281 to .193 in the last 20 games. He has especially struggled from the left side of the plate, where he entered Monday's game hitting .175.
"At some point, it becomes, 'I've got to get something going. I need to do something,' " Espinosa said. "And the pressing isn't good, but at some point you have to press hard. The first two balls I hit, I had to laugh those off. I couldn't get angry about those because I put two good swings on the ball. I'm not going to say I'm out of the slump 100 percent because it was just one hit, but I feel better. I feel like I'm going to carry this over."
Washington manager Jim Riggleman was confident that his young player would figure things out.
"On the left side, it's been a struggle. But he's a tough kid," Riggleman said. "He gave us a great at-bat."
Jerry Hairston Jr. also homered for the light-hitting Nationals, who managed just six hits.
Washington starter John Lannan scattered seven hits in 6 1/3 innings, allowing two runs. Lannan labored early, throwing 26 first-inning pitches and allowing an RBI single to Steve Pearce before settling down enough to keep the Nationals in the game.
"I'm kind of waiting for that game where I feel good all the way through," Lannan said. "They say for every 10 starts, you're going to have six good ones, two [lousy] ones and two OK ones. So I'm grateful that I can go out there and make the pitches I need to."
Cole Kimball (1-0) earned his first major league win in relief despite allowing the Pirates to draw even in the seventh inning. Lannan walked Ronny Cedeno and Maholm moved him to second with a sacrifice bunt. Andrew McCutchen then tripled into the right-field corner off Kimball to tie it at 2.
"I want John to keep that win," Kimball said. "It's exciting, but it's also my job not to go in there and give up the win."
Drew Storen pitched the ninth for his ninth save in as many chances.
Pittsburgh, losers of a season-high six straight, has scored just 14 runs for Maholm in his nine starts.
"I've seen teams try just a little too hard when one guy gets on the mound," Pirates manager Clint Hurdle said. "It becomes a little bit more challenging than it is ordinarily. We've not given him the run support we would have liked to in any way, shape or form."
Maholm had retired 12 batters in a row until the fifth inning, when Hairston hit a 3-1 pitch over the left-field wall for his second homer of the season to give Washington a 2-1 lead.
The Pirates ran themselves out of several scoring opportunities in the fourth. Brandon Wood was thrown out by Roger Bernadina attempting to go from first to third on a single by Chris Snyder. In the same inning, Snyder was caught in a rundown after a failed squeeze attempt by Maholm.
Washington RHP Todd Coffey pronounced himself fine Monday, one day after taking a liner off his right elbow that forced him out of Sunday's game. Coffey's swollen elbow was bandaged tightly, but said he could pitch Tuesday. ... Nationals SS Ian Desmond returned to the lineup after missing two games with a sore left hamstring. ... Pirates RHP Ross Ohlendorf (shoulder strain) played catch for the fourth straight day. No timetable has been set for him to pitch off the mound. Ohlendorf has been on the 15-day disabled list since April 9. ... The Nationals' six-run first inning Sunday was the biggest scoring output by the team in the opening frame since baseball returned to Washington in 2005. The last time a D.C.-based team scored six or more in the first inning was May 8, 1955, when the Washington Senators did it against Baltimore.