Terry Collins flipped the Byrd at conventional wisdom last night and watched his Mets lineup enjoy rare success.

Instead of using his lefty-hitting platoon players against Nationals right-hander Dan Haren, the manager — citing the numbers — went with a righty unit that included Marlon Byrd.

The numbers didn’t lie. Byrd hit two home runs for three RBIs, helping the Mets snap a four-game losing streak with a 10-1 victory at Nationals Park.

Haren, who relies on a cutter, had allowed lefty batters to hit .258 against him entering last night. Right-handed batters were hitting .321. Byrd in particular had tormented Haren, going 8-for-16 against him.

Byrd, who has hit eight home runs, actually predicted the two-homer game to teammate Anthony Recker during batting practice.

“I was feeling good in B.P. and I was joking around with [Recker],” Byrd said. “I said, ‘Hey, if I get some pitches tonight, get some strikes, I’m going to hit two home runs tonight.’ I didn’t think it was going to happen.”

But Recker said Byrd’s prediction wasn’t a joke.

”He was dead serious,” Recker said. “And he did it. That’s amazing to me. He called it. You don’t see that very often.”

Byrd, who homered in consecutive games against the Yankees last week, went deep in the second and third innings to finish with multiple homers in a game for the sixth time in his career.

David Wright also homered against Haren as part of the Mets’ 15-hit attack, giving Dillon Gee a comfortable cushion.

Gee (4-6) earned his second straight victory by holding the Nationals to one run on nine hits over seven innings. It came a night after Jeremy Hefner — Gee’s competition for the final spot in the Mets rotation once top pitching prospect Zack Wheeler arrives — allowed one run over seven innings.

”Luckily, I made the pitches when they really counted,” said Gee, who surrendered an RBI single to Ian Desmond in the first, but escaped trouble in the second and fourth innings. “That’s something I wasn’t doing early in the season.”

The Mets (23-33) got their first victory since sweeping the Yankees four games last week. They will go for a series victory over the Nationals tonight, when Shaun Marcum faces Gio Gonzalez.

Rookie Juan Lagares — part of Collins’ righty movement against Haren — finished 3-for-5 with three singles. Before the game Collins said Lagares might got a shot at playing regularly in center field as veteran Rick Ankiel continues to struggle.

“You watch [Lagares], he can run, throw, field, he’s got some power,” Collins said. “Is he going to hit up here? You’ve got to play him to find out, so we’ve been trying to pick the best opportunities to get him some at bats, but there’s some tools there.”