For the first 3½ games, the Patriots’ offense was productive but a bit off as it adapted to coordinator Josh McDaniels.

It felt a little clunky, like quarterback Tom Brady was wearing a trenchcoat three sizes too big, instead of one of his impeccably tailored suits.

There were a lot of players being run in and out, some in featured roles that haven’t proven very much (cough, Julian Edelman), a ton of personnel packages, and an unusual number of gadget and deception plays.

It just seemed as if Brady and the primary weapons that have guided this offense the past couple seasons, receiver Wes Welker and tight end Rob Gronkowski (with Aaron Hernandez out), were being made to adapt to the changes McDaniels wanted to bring. He obviously had his reasons, and I’m sure they were well thought out and researched. But it just felt a little much at times.

That all changed in the second half on Sunday against the Bills.

McDaniels worked with what he had, instead of making the Patriots something they are not.

McDaniels stripped it all down, from personnel, packages, and plays. Only a handful of each were used.

McDaniels started everything through Brady, and then attacked with the inside power running game the Patriots have been working on since the start of offseason workouts.

And, man, did it work.

On six successive drives in the second half, the Patriots racked up 330 yards and six touchdowns to run away with a 52-28 victory at Ralph Wilson Stadium.

Everything came together. McDaniels had figured out a way to perfectly mesh what had worked for the Patriots before his arrival, with his own twist.

The result was, finally, sweet music.

“I think we’re getting better,” Brady said. “I think that’s what we’ve shown, and you have to keep building on the good things and try to eliminate the bad things.”

Brady, who started 11 of 21 for 167 yards and no touchdowns, completed 11 of his final 15 passes for 173 yards and all three of his touchdowns.

The double-headed running game of Brandon Bolden and Stevan Ridley put up 159 yards and two touchdowns after halftime.

Talk about balance. The Patriots could do no wrong.

“We ran the ball really well,” Brady said. “That was a big point of emphasis this week.”

As it should have been, especially after the Bills showed no interest in playing their base defense against the Patriots.

Usual starting linebackers Kelvin Sheppard (middle) and Arthur Moats (strong side) didn’t even see the field until the game was out of hand and they had to sell out to stop the run.

Every other snap, outside of goal line, the Bills had their four down linemen, linebacker Nick Barnett, and six defensive backs, with strong safety George Wilson playing the role of linebacker.

If the Patriots can’t run against that personnel, they should give up.

“I think they were really challenging us to run the ball,” Brady said. “They had some little guys on the field with our big personnel groupings, so at that point you have to try and take advantage of it. You can’t just keep throwing into a heavy pass defense.”

Oh, but the Patriots have tried that in the past — including the 2010 playoff loss at home to the Jets — and failed.

The run game was certainly a key, as was eliminating the negative plays that plagued the offense in the first three games. The Patriots had just one on Sunday.