FOXBORO — For a while, Bailey Zappe went throw to throw with Patrick Mahomes and held his own. The second-year Patriots quarterback was nearly perfect in the first half and likely would have gone into halftime with a lead if not for some ill-timed offensive penalties.

But much like last week against the Steelers, Zappe’s hot start wouldn’t last.

Zappe threw a backbreaking interception on his first throw of the second half, allowing Kansas City to seize control of what had previously been a neck and neck game. Things progressively got worse from there and the end result was yet another poor offensive effort.

“Simply not good enough,” Zappe said after the game. “Starting out hot in the first half again like we did the previous week, came in here and made adjustments, understood what we wanted to attack, went out in the second half and threw an interception on the first play of the second half, which was terrible on my part. Take away that, you take away seven points, it’s a whole different game.”

Early on Zappe demonstrated the sort of consistency New England sorely lacked with Mac Jones under center. The 24-year-old signal caller went 17 for 19 with 141 yards, a touchdown and no interceptions, and he demonstrated a particularly strong connection with tight end Hunter Henry, who had six catches on six targets for 57 yards, four first downs and a 16-yard touchdown grab.

Zappe and Henry should have had a second touchdown connection too, but the score was nullified by a holding call and things went downhill from there.

The game turned on Zappe’s third quarter interception and reached its nadir early in the fourth, when Zappe nearly threw another pick and on the next throw left Henry defenseless against an oncoming hit. Henry subsequently went to the blue tent with a knee injury and did not return.

When all was said and done Zappe went 6 for 12 with 39 yards and a pick in the second half, and the Patriots offense collectively managed only 57 yards on 22 plays. New England scored a late touchdown thanks to a Jahlani Tavai interception and an 18-yard touchdown run by Kevin Harris, but even trailing by only 10 in the final minutes it never felt like the Patriots were a real threat.

“We had some opportunities there, some opportunities to put some more points on the board, but we really didn’t,” said center David Andrews. “Look when you’re playing a good team like this, a good defense, a good offense, you’ve got to score points. You have to score as many as you can and we didn’t do a good enough job of that today.”

Zappe’s disappointing second half continued what is shaping up to be a troubling trend. Zappe also faded down the stretch late against Pittsburgh last week, going only 5 for 7 with 44 yards and an interception after a brilliant first half, though in that case New England was still able to pull out the win. He wasn’t particularly effective at any point in his first start against the Chargers either, going 8 for 13 with 102 yards in the second half of that week’s 6-0 loss.

Is Zappe struggling to adapt to the opposing defense’s halftime adjustments? He said today that wasn’t the issue, he just needs to do a better job himself.

“They adjusted and we adjusted, I just didn’t execute our adjustments, and that was the difference,” Zappe said. “I’ve just got to get better.”

Whether Zappe can turn things around over New England’s last three games almost makes no difference, the Patriots are already eliminated from playoff contention and consigned to a third losing season in four years. But if Zappe wants to prove he can be a winning quarterback in the NFL — either in New England or someplace else — he’ll need to not only elevate his level of play, but maintain it for a full 60 minutes.