Mets 7

Nationals 1

WASHINGTON – The uncertainty was there not just for Brian Bannister but as a result for the fifth spot in the rotation, period.

Bannister had a terrific spring training for the Mets, and there had been some success for him in the minors. But the 25-year-old rookie was unproven until a week ago since he’d never been in a major league game. And as the fifth starter, the Mets – a team for which October needs to be an active month of this season – needed Bannister to deliver.

Bannister pitched well last Wednesday against the Nationals in his major league debut before getting a no-decision. Yesterday, he earned his first big-league victory, scripting perhaps the Mets’ best pitching performance of the year so far.

Bannister pitched seven innings against the Nationals in the Mets’ 7-1 rout yesterday, allowing just three hits and one run while walking nobody.

“He was in command the whole game,” catcher Paul Lo Duca said.

And for the most part, the Mets have been in command for this whole six-game season. They’ve won four straight and are 5-1, which is their most promising beginning in over 20 years. In 1985, they began 8-1.

Meanwhile, the Mets have played 55 innings this season and have trailed for only two of them.

One of those frames wasn’t yesterday. After limiting the Nationals to no hits over his first 51/3 innings last Wednesday at Shea, Bannister held Washington scoreless for his first 62/3frames yesterday. He then gave up a solo homer to Alfonso Soriano. The other two hits were singles, and with no walks or hit-by-pitches, Bannister never allowed more than one man to reach base per inning.

If Bannister can sustain his level of pitching, the Mets’ rotation could be pretty powerful. So far, Bannister is proving that he belongs.

“They gave me the leap of faith to put me in the rotation right away. It’s a compliment, and I’ve just tried to take advantage of it, like I did in spring training given those opportunities,” Bannister said. “And it’s one of those things, I’ve got to get over my own fears of being out there and do I belong here, and once that happens, then I feel like I’m going to be a part of this team and really just rely on these guys to win games.”

The Mets provided 12 hits for Bannister yesterday, though actually that’s a little misleading. The team had 12, but Bannister had two himself, a single and a double. He also scored a run.

As for the rest of the lineup, Jose Reyes and Carlos Beltran both had two hits and two RBIs (Beltran belted his second homer of the year), while Lo Duca had three hits and an RBI. The Mets scored two runs in the fourth and led 5-0 until Soriano’s homer in the seventh.

Over the first three innings, Bannister recorded five of his nine outs on the ground (he struck out one and had three outs in the air during that time). But from the fourth through the sixth, he got all nine outs in the air. Then in the seventh, he got his first two outs on the ground before a fly-out to end his outing.

“You kind of see patterns,” Bannister said. “Each time you go through the lineup, you try and do something a little different just so the hitters don’t see a pattern and they don’t get into a rhythm. And I think that’s just the result of that.”

Bannister got the lineup card from the game as well as the baseballs from his first hit and the triumph. The rookie is 1-0, and the Mets are 5-1.

mark.hale@nypost.com