Nick Bosa is happy with his new friends on the San Francisco 49ers defensive line.

Maliek Collins weighs in at 310 pounds, has a thick beard and a sly smile. Collins joined the 49ers after making 112 starts in eight seasons with the Cowboys, Raiders and Texans. He knows a thing or two about filling the middle.

Leonard Floyd weighs in at just 240 pounds, small but fast. Floyd joined the 49ers after starting 120 games in his eight seasons with the Bears, Rams and Bills. He knows a thing or two about rushing the passer.

Considering their San Francisco debut on Monday night, Collins and Floyd will get along well with Bosa.

Forget Aaron Rodgers for a moment. The 49ers sailed to an impressive 32-19 victory at Levi’s Stadium, largely because they smothered the New York Jets’ running game.

The Jets managed just 68 yards on the ground, with just 31 of those coming in the first three quarters (by which time the game was essentially decided). Collins did his part, jamming the line of scrimmage and picking up a New York fumble in the first quarter to set up Jake Moody’s first field goal.

Floyd also contributed by tackling Rodgers early in the second quarter to force a Jets punt. The 49ers then drove downfield to score the go-ahead touchdown, taking a lead they would never relinquish.

Which explains why Bosa walked into his postgame press conference in an unmistakably buoyant mood. Not only did the 49ers win their season opener, they also showed off a revamped defense—and as always, the comparison starts on the line.

“Floyd is just a ball of energy and he can run,” Bosa said. “People think he’s a smaller, skinny guy who can’t run, but he’s explosive as hell and he can run the way we need him to. Obviously he can rush (the passer), he’s proven that throughout his career.

“And then Maliek is a beast in the run game. If he can do that all year, we’ll be good.”

The 49ers entered the season with lingering questions about the defense. They baptized a new, inexperienced defensive coordinator in Nick Sorensen. They played without Arik Armstead (a salary cap casualty), Dre Greenlaw (recovering from a torn Achilles) and Talanoa Hufanga (nearly back from a torn ACL).

But the defense still looked just as fearsome.

Rodgers led the Jets on an impressive first-half drive, a 12-play, 70-yard march to a touchdown. New York’s other possessions before halftime produced this meager output: 7 yards (culminating in a punt), 2 yards (fumble), 0 yards (punt), 5 yards (punt), minus-1 yard (end of half).

The Jets stubbornly tried to establish their ground game with third-year running back Breece Hall, who once played at Iowa State next to a quarterback named Brock Purdy. Hall carried the ball 10 times in the first half, gaining just 25 yards.

That’s been a big part of the 49ers’ success in recent years. They ranked third in the NFL in rushing defense last season, second in 2022, seventh in 2021 and seventh in 2020.

“That’s our main focus every year,” Bosa said. “When you make teams one-dimensional, that’s huge. It’s always our main focus, especially with our D-line scheme and the way we make our linebackers play.

“We are very proud of it, and last year we were not as good as we should have been. So we had to improve.”

Bosa was quiet Monday night, with two quarterback hits but no sacks. He also drew a lot of attention, as usual – at one point a Jets offensive lineman wrapped Bosa in a bear hug/head lock to keep him away from Rodgers (somehow no penalty was called).

The 49ers naturally expect opponents to target Bosa, so it becomes all the more important for other defensive linemen to make an impact.

The presence of linebacker Fred Warner doesn’t hurt either. Warner forced Hall’s fumble on New York’s fourth play from scrimmage, setting the tone for what became a mostly energetic defensive effort.

The Jets scored two touchdowns in the final 18 minutes of the game, one while trailing 26-7 and the other while scoring 32-13.

One interested observer: Patrick Willis, the Hall of Fame linebacker. Willis, who visited the 49ers’ locker room after the game, acknowledged that the defensive effort helped ease concerns about midseason changes.

“They lost a couple guys to free agency and some injuries, so there was some uncertainty,” Willis said. “But for the first game, it felt like they filled those holes and played good defense.”

As always, head coach Kyle Shanahan and general manager John Lynch tried to bolster their defense by adding linemen. Last year, they signed Javon Hargrave, a two-time Pro Bowl selection. This past offseason, they acquired Collins and Floyd.

The (very) early results are encouraging.

Contact Ron Kroichick: [email protected]; Twitter: @ronkroichick