A back-and-forth contest for the top-of-the-heap in the N.L East, and one of the most exciting games of the night, saw the Washington Nationals victorious in the 12th inning on a sharp single to left field from rookie Bryce Harper. Harper’s game winning RBI gave the Nationals a 7-6 victory, and the first triumph over the Mets in a three game series.

For a time, at least, the home town crowd of 26,000-plus might have easily assumed that the Mets would emerge victorious from the contest — they’d taken the lead in the 8th and 10th innings, only to see the never-say-die Nationals either tie the game or take the lead. The same was true in the 12th, with the Nationals down by one.

The crucial bottom of the 12th began with a Michael Morse double, his second of the game. Ian Desmond followed with his own double, scoring Morse and tying the game. But the still-struggling Danny Espinosa flied out, with Desmond moving to third. That’s when the trouble started for the Mets, as reliever Elvin Ramirez intentionally walked Jesus Flores and then loaded the bases with a head-scratching walk of Nats’ pitcher Ross Detwiler.

Even with the bases loaded, however, the Mets had a good shot at sending the game into the 13th. Late inning substitution Xavier Nady grounded to first baseman Ike Davis, whose throw home nabbed Desmond on a force out. But after two nifty strikes (and with an 0-2 count), Harper ended the contest on an emotional slap line-drive to left field — and was mobbed by his teammates.

“I knew [Ramirez] didn’t want to walk me, so I knew he was going to come over the plate, but I got a pitch I could handle and threw my hands at it,” Harper said, following the victory. “It was a good ‘W’ tonight. That was huge.” Davey Johnson was also pleased with the outcome, while noting that both teams might have won the game at any point. “Wild game. It wasn’t a very well-played game, but it was nice to come out on top,” he said.

Nationals fans could have been excused for hoping that they would see a pitchers’ duel, with Jordan Zimmermann facing off against Chris Young. Zimmermann pitched true to form — giving up only five hits over six innings — but the Mets continued to sneak back into the contest: victimizing Sean Burnett, Craig Stammen and Henry Rodriguez to even the score at 5 in the eighth and then at six in the tenth.

But the aftermath of the triumph featured Harper, who was 2-7 on the night and is now hitting .288. “I’m pretty [upset] that I went 2-for-7,” Harper said. “I’m happy with the ‘W,’ of course, and I’m happy to get that walk-off hit. But I don’t like to go 2-for-7. I don’t like striking out twice in one game, either.”