With the series win, the Nats improved to 19-15 and are alone in second place in the National League East, trailing only the Phillies.
The game was tied at 4 in the top of the ninth when Bernadina hit an 0-1 pitch from closer Francisco Rodriguez (2-1) over the right-center-field fence for a two-run homer to give Washington a two-run lead.
"He is just too good to be sticking [a hit] out there now and then," Riggleman said. "The coaches agreed. They all felt the same way that Roger is ready to break out. It's one game. It's not a breakout. It could be the start of something good. It couldn't happen to a more wonderful kid. Again, we are lucky to have him."
Washington has been searching for a right fielder since it released Elijah Dukes in late March and it is hoping that Bernadina can win the job outright. For the moment, he is getting the most playing time against right-handed pitchers.
"I take it day to day and I'll see what happens from there," Bernadina said. "I'll do whatever I can to stay there. The manager makes his decisions. I'll take care of myself, whenever I'm on the field."
There was a time last year and this season when Bernadina wondered if he would ever get his chance to shine in the big leagues. Highly touted for several years by assistant general manager Bob Boone and Tim Foli, the senior assistant to general manager Mike Rizzo, Bernadina was given a chance to play in 2009, but his season was cut short in April when he fractured his right ankle making a spectacular play in center field against the Marlins.
Early this season, Bernadina was called up from Triple-A Syracuse, but was sent down three days later because the team was going to face a lot of left-handed pitchers. Bernadina acknowledge that he was down, but he vowed that he wasn't going to let the demotion hurt his career.
"When they sent me down, I was down about it. But I said, 'I wasn't going to let anybody hold me down,'" he said.
Before being recalled from Syracuse on April 28, Bernadina was named the International League Player of the Week for hitting .464 with a homer and six RBIs.
"When he plays real well, Bernie has a nice feel and a nice relaxation," Foli said. "We know what kind of talent he has. You have to remember that Bernie didn't play that much last year. He needs to play. The more reps he gets, the better he is going to be. He is a great athlete. It's kind of exciting."
Thanks to Bernadina, Tyler Clippard won his seventh game, which leads the National League, while Matt Capps picked up his 14th save in as many chances.
Right-hander Craig Stammen picked up a no-decision and jokingly asked Clippard if he could start wearing his underwear so he could start getting some victories.
"He said, 'No,'" Stammen said. "He is doing great. We are playing a lot of close ballgames. He has been in there in the end and he comes in there when it's tied. He shuts them down and deserves those wins."
Stammen wasn't as effective as he was against the Marlins last week. He lasted five innings, allowed four runs on seven hits, struck out two and walked two.
However, Stammen had a great day at the plate, going 2-for-2 with three RBIs. The last pitcher in franchise history with three RBIs was right-hander Guillermo Mota against the Red Sox on June 9, 1999.
"When I go up there, I'm a very competitive person and I'm not going to back down," Stammen said. "I'm not going to give up an at-bat. I had a chance to keep myself in the ballgame. If it wasn't for those hits, I would have been out of the game a little earlier."
Stammen drove in the game's first two runs with a single to left field to score Adam Dunn and Cristian Guzman. Two innings later, Stammen singled to center to knock in Wil Nieves.
With a 4-2 lead, Stammen allowed the Mets to tie the score in the bottom of the fifth. Angel Pagan scored on a single by Alex Cora, while Cora scored the tying run on a double by Jose Reyes.
The game could have gotten out of hand if not for Bernadina in the same inning. With the bases loaded and two outs, Bernadina robbed Jeff Francoeur of extra bases on a diving catch.
"He ruined my day," Francoeur said. "This stinks, man. The way he played, he was the right guy at the right time. That balls falls in, it's over."
Stammen was not surprised to see Bernadina make that catch.
"I've seen him jump over the wall to catch balls," Stammen said. "I've seen him hit home runs. He is a really good athlete. He is almost as close as there is to a five-tool player. That's good to see that he broke out today."