Archie Gilbert leaned on his back foot and looked up at the cloudy sky.

His teammates began to laugh. Fellow players seated in foul territory buried their faces in their shoulders as they started to giggle.

After realizing what happened, Gilbert finally cracked a smile and shook his head.

On his first swing of the Class AA Eastern League Home Run Derby on Wednesday in Manchester, N.H., the Washington Nationals prospect fanned on a slow pitch down the middle of the plate.

“I’m definitely the only one to do that,” Gilbert said with a laugh. “That was nerve-racking. I tried to really dig in there and crush it. Oops.”

Gilbert was the only of eight contestants who failed to park a ball during the derby. Harrisburg Senators teammate Tyler Moore was eliminated in the tiebreaker of the first round.

Gilbert and Moore were two of six Nationals farmhands selected to the Eastern League All-Star Game, which was preceded by the home run derby.

Moore led off the festivities and launched one of his five allotted swings over the left field fence, putting him in a three-way tie for fourth. Moore sent another liner over the left field porch, about 340 feet from home plate, in the tiebreaker, but was outdueled by Phillies prospect Matt Rizzotti, who captured the last semifinal spot.

“Man, that was tougher than it looked,” said Moore, a 6-foot-2 first baseman.

In a park benefiting lefties, Gilbert and Moore were at a clear disadvantage. The 306-foot right field fence made life easy for southpaws Rizzotti and Mike McDade, who was edged out by fellow Blue Jays prospect Moises Sierra in a final that went to three tiebreakers.

“For a while, I thought about trying to go opposite field with it,” said Moore, 24, a 16th-round pick of the Nationals in 2008 who was the franchise’s minor league player of the year last season. “But you can’t try to do that in a home run derby.”

Gilbert, a 27-year-old outfielder, said has a tough time generating power on slow pitches and uses the speed of a in-game pitches to drive the ball.

“I’ve never been good at this stuff,” Gilbert said. “I can hit for power in a game with the adrenaline going and the pitcher bringing it, but this stuff is hard for me. They wanted [Harrisburg teammate Bill] Rhinehart for this, but he didn’t want to do it. So I told them I would.”

Gilbert, signed by the Nationals as a free agent last December, has 10 homers this season for Western Division-leading Harrisburg. Rhinehart leads the Senators with 19 and Moore is second with 18.

There was a friendly rivalry between Moore and 5-foot-8 Gilbert, though.

“They definitely wanted to beat each other,” Harrisburg pitcher Erik Arnesen said. “It’s just a friendly rivalry though – nothing serious.”

That doesn’t mean Moore won’t have some fun at Gilbert’s expense after his big swing and miss on the first pitch.

“I haven’t said anything to him yet,” Moore said, “but I’m going to have to give him some grief later.”