CHARLOTTE — The Panthers defense is doing all it can do.

At least, what's left of them.

The Panthers again watched a solid defensive effort go in vain with an offense that couldn't muster much, losing 37-15 to the 49ers to fall to 1-4.

Carolina lost cornerback Jaycee Horn late in the third quarter with a hip injury, and they started the game without three of their four leading tacklers, with linebacker Frankie Luvu (shoulder) and safety Xavier Woods (hamstring) inactive and safety Jeremy Chinn (hamstring) on injured reserve.

Those that were left did a creditable job.

Linebacker Damien Wilson forced a fumble (recovered by Yetur Gross-Matos), and defensive tackle Derrick Brown blocked a field goal attempt (and batted down another couple of passes, giving him six in five games after he totaled eight his first two seasons).

But for all their efforts, the Panthers were undone by an offense that again couldn't sustain enough drives.

They entered the game last in the league in third down conversions and managed just 3-of-15 Sunday.

Quarterback Baker Mayfield occasionally found some plays downfield (hitting DJ Moore, Robbie Anderson, and Shi Smith for gains of at least 27 yards), but he also threw a pick-six just before halftime to send the Panthers into the break down 17-3.

Mayfield finished the game 20-of-36 for 215 yards with that interception.

When they opened the second half with an impressive touchdown drive (capped by a 19-yard touchdown run by Christian McCaffrey), they went for a two-point conversion and failed, and never recaptured that momentum.

Mayfield, whose left foot was rolled up on late in the first half, was replaced by PJ Walker for the Panthers' final series.

— Panthers cornerback CJ Henderson again found himself on the wrong side of a costly penalty.

His pass interference call on a fourth down in the third quarter kept a 49ers' drive alive, and they scored a touchdown later that possession.

Henderson's a talented player, but when he makes mistakes, they show up in big ways. With Horn out of the game late, they looked even bigger.

— The Panthers might have found a kick returner, with rookie running back Raheem Blackshear popping a couple of big ones.

He had a 45-yarder and a 48-yarder, and finished the day with six for 184 yards. That's the third-highest single-game total in franchise history.

— Kicker Eddy Piñeiro missed his first field goal attempt of the season in the first quarter. He had hit his first eight attempts with the Panthers and 27 in a row overall.

He bounced back to hit three more to start a new streak, and has provided solid kickoffs, as he has since taking over for the injured Zane Gonzalez.