DeAndre Baker had spoken with such confidence this past week, days after his indoctrination into the NFL had gone so poorly in Dallas in the season opener.

“My confidence is way higher now than going into the first game,’’ the rookie cornerback told The Post’s Paul Schwartz on Wednesday.

The truth is, it didn’t look a lot better for Baker in his second NFL game, Sunday’s 28-14 loss to the Bills at MetLife Stadium, than in his first.

Not when he was giving up a 26-yard pass play in the first quarter, leading to Buffalo’s first touchdown.

Not when he was giving up a 12-yard completion on third-and-10 from Josh Allen to Cole Beasley, leading to Buffalo’s second touchdown.

Not when he appeared to be the culprit on a 51-yard Allen completion to Beasley on first-and-20, leading to Buffalo’s third touchdown.

Just as the Cowboys did last Sunday, the Bills targeted Baker, the 30th pick in April’s draft, and the growing pains continued.

“You just have to have short-term memory,’’ Baker said after the game. “It’s always [about] the next play. So just forget about last play. You can’t redo it, so make sure it doesn’t happen again. Just learn from it. It’s all about learning.”

Baker conceded that he’s had some difficulty adjusting to the NFL-level talent after starring at Georgia.

“Right now, I’m not playing as fast as I could be,’’ he said. “But that just comes with the preparation and timing. Within our room, the guys are helping me get the scheme right. It will come.’’

Giants coach Pat Shurmur believes it will.

“He’s a rookie corner and he’s learning how to play the game at this level,’’ Shurmur said. “I think he keeps challenging and he’ll keep getting better, because he has the skill and the ability to do it.’’

Janoris Jenkins, the Giants veteran corner who also had some poor spurts in the game, remained bullish on his rookie teammate.

“I mean, it’s tough, but you just can’t say DeAndre Baker,’’ Jenkins said. “You got to look at the whole defense, everybody [is at fault]. There are 11 people on the field at all times. You got to look at everybody. You can’t just say, ‘Rookie this, rookie that.’ ’’

Asked about teams targeting Baker, Jenkins said, “Hey man, you just got to buckle up and play football. Forget who they’re going at.’’

Jenkins, perhaps out of frustration, slipped into a moment or two of accountability issues after the game.

Asked about the problems in the secondary this week compared to last week, Jenkins said, “It wasn’t nothing. Did a receiver score?’’

Um, no.

“Well, OK, we played great in the secondary; we just got to step it up a little more,’’ he added.

Yes, but what about all of those damaging third-down conversions the defense allowed, which kept Buffalo scoring drives alive all day?

“Yeah, we got to come through, man, as a defense and get off the field on third down,’’ Jenkins said.