Believe it or not, there were signs in that sad, rain-soaked, shutout loss to the Chargers.

Signs of a stirring deep passing game. Of improved pass protection. Of an offense that might one day meander back to the end zone after making one such trip in its last three games.

Then the Patriots made that trek three times Thursday night, all in the first half. Bailey Zappe posted a sparkling 115.2 passer rating and matched Mac Jones for the season when he hit his fourth deep pass on the year. Zappe also became the first Patriots quarterback to throw three touchdown passes in a first half since Tom Brady in 2018.

How much of that is sustainable moving forward, especially in light of a scoreless second half? Likely not much.

Zappe’s leading receiver, JuJu Smith-Schuster, earned more than 40% of his season-high 90 yards on a low-percentage contested catch. Ezekiel Elliott caught seven passes for the first time in two years. Zappe also peaked with his offensive line, which allowed a season-best 16.7% pressure rate.

But there are elements worth monitoring here. Over two and a half games, Zappe is protecting the ball better than Jones did. He’s threatening defenses downfield in a way the Patriots haven’t most of this year. And up front, offensive linemen Trent Brown, Cole Strange and David Andrews are giving him time, having allowed just a single combined pressure the past two weeks.

To be clear, Zappe is no more the passer he was in the first half at Pittsburgh than he was in the second (44 passing yards, zero touchdowns, one interception). But Zappe is proving himself worthy of a longer leash, which was hard to imagine after his flops in mop-up duty versus the Cowboys, Saints, Colts and Giants; almost as hard as picturing the Patriots in the end zone.

Yet there they were, three times Thursday, thanks partly to their new starting quarterback.

Here’s what else the film revealed about Thursday’s win:

Accurate throw percentage: 80.8%

Under pressure: 1-of-3 for 17 yards, 2 sacks

Against the blitz: 4-of-7 for 73 yards

Behind the line: 5-of-5 for 49 yards

0-9 yards downfield: 10-of-15 for 105 yards, TD, INT

10-19 yards downfield: 2-of-2 for 25 yards, TD

20+ yards downfield: 2-of-4 for 61 yards, TD

Notes: Considering the stone-wall protection his offensive line provided, Zappe should have at least managed an average passing performance. And that he did.

But more than his touchdowns to Hunter Henry and 37-yard completion to Smith-Schuster, pocket presence defined his game. Zappe maneuvered every type of pocket well; stepping up when he needed to step up, sliding when he had to slide and taking off when scrambling offered the best option. All of that dodging, ducking, dipping and diving allowed him to find safe platforms from which to throw or extend the play.

Quarterback play under pressure is not often consistent week to week, but in the face of a closing pass rush, Zappe has kept the Patriots afloat enough after Jones too often sank them in the same situation. Zappe also chucked two throwaways, a small number that matches Jones’ output from his last three starts combined. For a defensive team, the quarterback opting for a throwaway instead of a sack or turnover can change a game.

Now Zappe did throw a tip-drill interception and risked another pick in the second half, after which offensive coordinator Bill O’Brien seemed to take the game out of his hands with run-heavy play-calling. But overall, Zappe managed well without leaning heavily on play-action or screen concepts and posted the second-highest accurate pass percentage of his career. That’ll work.

The ex-Steeler caught four passes for a season-high 90 yards, including two explosive plays that powered the Patriots’ highest-scoring first half in almost two years. His 90 yards were also a personal best in almost 14 months.

A throwback, workhorse performance from Elliott, who played 52 of 57 offensive snaps. His 140 total yards not only led all players Thursday, but marked a new season high.

Dugger made his imprint on the game foremost as a blitzer (four pressures), but also broke up a pass and discouraged Trubisky from making other throws underneath.

Jennings led all Patriots with three tackles for loss, two run-stuffs and tossing Steelers tight ends around like a game of catch. Great game, perhaps the best of his career.

Jackson allowed the Steelers’ first touchdown and got flagged twice for pass interference penalties. There is no player the Patriots ride a week-to-week roller coaster with his performance quite like Jackson, who hit another severe low Thursday.

Montgomery was replaced on punt protection after the second-half punt block and dropped a pass on offense.

The rookie right guard allowed a team-worst three pressures and was closest on both of Zappe’s sacks.

Statistics for passing depth, broken tackles and missed tackles courtesy of Pro Football Focus.

*Explosive plays are defined as runs of 12-plus yards and passes of 20-plus yards. Explosive play rate is one of the most strongly correlated metrics with wins and losses.

**Success rate is an efficiency metric measuring how often an offense stays on schedule. A play is successful when it gains at least 40% of yards-to-go on first down, 60% of yards-to-go on second down and 100% of yards-to-go on third or fourth down.

***11 personnel = one running back, one tight end; 12 personnel = one running back, two tight ends; 13 personnel = one running back, three tight ends; 21 = two halfbacks, one tight end.  

****Base defense = four defensive backs; nickel defense = five defensive backs; dime defense = six defensive backs; dollar defense = seven defensive backs.