SANTA CLARA, Calif. – Za'Darius Smith has flashed a lot of creativity when it comes to the sack celebrations he's utilized during his career year in 2019.

However, Sunday night's was easily the most meaningful to the Packers' defensive captain and fifth-year linebacker.

As a tribute to the ailing mother of one of the team's equipment assistants, Smith wore a hand-drawn "We (Heart) Eileen" shirt underneath his No. 55 jersey, which he showcased after his 10-yard sack of San Francisco quarterback Jimmy Garoppolo on second-and-20 early in the second quarter.

It was an idea Smith and the assistant, whom Smith didn't want to identify, came up with after Green Bay returned from its Week 11 bye. Before the game, the assistant drew the message on Za'Darius' white undershirt with a red marker.

"He had been talking about his mom," Smith said. "We had just gotten back off the bye week. I talked to him. He was like, 'Man, we should do something for her.' I was like, 'Why not that be my sack celebration to shout her out?' He came up with the idea to shout her out and it all came through."

Until this point, Smith has used everything from karate kicks, crawling on his stomach and even sleeping on his side to commemorate his sacks.

After dropping Garoppolo, however, Smith locked eyes with an NBC camera in the end zone, plainly lifted his jersey up and pointed to the words on the shirt.

Smith combined with Preston Smith on another sack at the start of the first half to give him 10 on the season, which marks the first time in his career Smith has hit double digits in sacks in a season. He led the defense Sunday night with six tackles (two for a loss), three quarterback hits and the 1½ sacks.

With Preston now at 10½ sacks on the year, the Smiths are only the second pair of Packers' pass rushers to have 10-plus sacks in the same season since it became an official stat in 1982. Reggie White and Bryce Paup were the first to do it in 1993.

His opportunity to honor the member of the equipment staff was a special moment for Smith and the rest of the team during an otherwise disappointing 37-8 loss to the 49ers.

"Emotional, emotional story for me," Smith said. "I was like, 'Man, we should do something for her because she's a big fan.' We came up with the idea to do the shirt and I was like, 'Wouldn't it be cool if I do that as my next sack celebration?' So I did that for her tonight. … I hope she gets that message."

Defensively, the Packers started strong against the 49ers in containing them to only 10 points in the first quarter despite an early turnover giving San Francisco the ball at Green Bay's 2-yard line.

However, big plays continued to hurt the unit. San Francisco hit six plays of more than 20 yards and two of more than 40, including tight end George Kittle's 61-yard touchdown in the third quarter that answered Green Bay's only scoring drive.

Garoppolo finished with a 145.8 passer rating on 14-of-20 passing for 253 yards and two touchdowns. Kittle, in his first game back after missing two games with an ankle injury, was responsible for more than half of that yardage (six catches for 129 yards).

The Packers will look to get back on track next Sunday when they travel to face the New York Giants.

"It's hard, man," Smith said. "I know one thing. It leaves a bad taste in all of our mouths. We just have to go in tomorrow and watch the film and see what we did wrong. I think we got outcoached and outplayed by this team. Just go in (Monday) and watch the film and correct our mistakes."