PITTSBURGH >> San Francisco coach Jim Tomsula’s homecoming ended with his team looking more like a homecoming opponent.

The 49ers had no answer for the Pittsburgh Steelers and their hyperdrive offense in a 43-18 loss on Sunday. The defense gave up 453 yards in 23 minutes. The offense struggled converting long drives into points and their ever-blunt leader was hardly didn’t try to spin the first loss of his career even if it came a few miles up the Monongahela River from where he grew up.

"They got after our tails," he said.

And never let go.

Ben Roethlisberger passed for 369 yards and three touchdowns, DeAngelo Williams tied a team record with three rushing scores and the Steelers (1-1) seized the momentum from a pair of early 2-point conversions on their way to a surprisingly easy victory.

"We’ve got a lot of work to do," Tomsula said. "We’ve got to keep going. It’s a 16-game season. We’re not going to overreact when we win. We’re not going to overreact when there is a loss."

Colin Kaepernick threw for 335 yards and two scores. Torrey Smith had six receptions for 120 yards and a touchdown, but the 49ers were no match for the Steelers’ firepower. San Francisco ran 77 plays and controlled the ball for long stretches

Controlling the game, however, was another matter entirely.

Plodding while the Steelers were sprinting, San Francisco couldn’t keep pace. Three drives of at least 15 plays — one in the first half and two in the second — netted only three points. Kaepernick was sacked five times and struggled to get comfortable until it was far too late.

"Obviously with the offense the Steelers have, we have to match the touchdowns," Kaepernick said. "We didn’t do that today."

Pittsburgh raced to a 26-point halftime lead and cruised, with Roethlisberger doing whatever he wanted while guiding an offense that looks to be every bit as dangerous as it was a year ago when the Steelers won the AFC North and finished second to New Orleans in yards.

Given 10 days to recover from a 28-21 loss to New England, Pittsburgh responded by looking every bit as explosive as offensive coordinator Todd Haley insisted it could be, even with All-Pro running back Le’Veon Bell and wide receiver Martavis Bryant suspended for violating the league’s substance abuse policy.

The 49ers opened the post-Jim Harbaugh era with a methodical 20-3 victory over Minnesota last Monday. On the other side of the country six days later, the going was far more treacherous.

There seemed to be little San Francisco could do to rein in Pittsburgh’s Antonio Brown, who hauled in nine passes for 195 yards and a score and one of the two-point conversions. Roethlisberger averaged 13 yards per completion and wasn’t sacked as the Steelers ripped off yardage in super-sized chunks.

"They threw the ball over my head several times and I can’t do anything about that," San Francisco linebacker NaVorro Bowman said.

While the 49ers saw long marches end with a field goal or a botched fourth down, the Steelers ended theirs with exclamation points. Pittsburgh’s offense stayed on the field following a pair of early scores, opting to go for two than a traditional one-point extra point at the new distance of 33 yards.

Both times the Steelers converted with ease.

"We’re going to take our shots," Brown said. "It’s another opportunity to put points on the board."

When San Francisco did threaten briefly in the second half following a 75-yard strike from Kaepernick to Smith that cut the deficit to 18, Pittsburgh went 80 yards in five plays to push it back to 25 and send Tomsula and his team back west with plenty to work on.

NOTES: 49ers RB Carlos Hyde ran for 43 yards before leaving in the second half following a shot to the head. He was cleared by doctors to return but was held out as a precaution. … Steelers LB Ryan Shazier had a career-high 15 tackles but left with a minor right shoulder injury. … Roethlisberger tied Terry Bradshaw’s team record for career wins (107). … San Francisco plays at Arizona next Sunday.