EAST RUTHERFORD, N.J. -- It was the pick-me-up the 49ers needed Sunday, and it came from sources both predictable and unexpected.
The defense returned to form by causing four turnovers, but it was Colin Kaepernick's cameo as a relief quarterback that stunned the New York Jets in a 34-0 shutout.
It was the 49ers' biggest shutout win since Oct. 4, 2009, against St. Louis (35-0) and their first road shutout since the 2001 regular-season finale at New Orleans (38-0).
Defensive heroics aside, coach Jim Harbaugh said it was time "for some creativity" on offense after last Sunday's first loss of the season, at Minnesota.
Enter Kaepernick, Alex Smith's second-year backup who seized upon his most significant action as a pro, albeit in a limited role.
"He got in and really executed well," Harbaugh said. "He played with great poise and made some pretty big plays for us."
The 49ers took a 7-0 lead on Kaepernick's 7-yard touchdown run early in the second quarter, and that was all the scoring necessary against the overmatched Jets (2-2). As a result, the 49ers still haven't lost two in a row since Harbaugh arrived last season.
"I'm hoping they will use me more and more as the season goes on," said Kaepernick, whom the 49ers moved up to grab in the second round of the 2011 draft.
Kaepernick could have scored once more but, after dashing 30 yards, he slid down at the Jets' 3-yard line with 1:12 remaining. His rationale: "We can end the game with no more collisions or chance of injury."
Kaepernick's first snap resulted in a 17-yard run for a third-down conversion, and his second was a bomb to Randy Moss into triple coverage at the goal line that was underthrown and fell incomplete.
Kaepernick finished with five carries for 50 yards -- including two kneel-downs for minus-4 yards to kill the clock as he relieved Smith for the final series. Kaepernick's other carry before Sunday's game: a 17-yard keeper in the season-opening win at Green Bay.
Smith didn't mind watching those plays from the sideline, including Kaepernick's first touchdown of his career on that 7-yard keeper 1:23 into the second quarter.
"It was fun (and) effective, for sure," Smith said. "He's a good player and I'm happy for him. He works extremely hard and can help this team."
Kaepernick and the 49ers' season-high 245 rushing yards were complemented, as usual, by their defense, which forced four turnovers and made the Jets go 2 for 13 on third-down conversions.
As was the case last season after their three defeats, the 49ers won without allowing a touchdown.
Instead, the 49ers defense scored a touchdown of its own, doing so on Carlos Rogers' 51-yard fumble return of Santonio Holmes' bizarre, unforced fumble.
"We got some gifts on defense and got in the end zone, so it was fun," said Rogers, who also recovered a fumble that Dashon Goldson forced in the second quarter.
The 49ers outgained the Jets 379 yards to 145 yards. Adding to that dominance was Larry Grant's block of a Jets punt in the fourth quarter, setting up Kendall Hunter's 1-yard touchdown run to cap the rout.
Harbaugh said of Grant's block and the four take-aways: "That's opportunistic football."
Jets embattled quarterback Mark Sanchez was 13 of 29 for 103 yards with an interception by Patrick Willis. Sanchez got sacked three times, and he fumbled on one of Aldon Smith's two sacks.
Just as with last year's layover in the Youngstown, Ohio, region, the 49ers capped their extended trip with an impressive win. Last season, they rallied 24-23 at Philadelphia to launch their playoff push. This season, they're 3-1 at the quarter pole, which became their goal as of a week ago, according to Alex Smith.
Smith, by the way, downplayed any hint of a quarterback controversy. Asked whether he minded being on the sideline while Kaepernick got summoned for the 7-yard touchdown, Smith replied: "That's not an issue. I don't care. We scored."
The Jets, of course, did not score.
"That's more like it, as they were saying in the locker room," Harbaugh relayed.
The 49ers then headed back to the Bay Area for a three-game homestand, opening next Sunday against the Buffalo Bills (2-2).
Rogers' daring suggestion: "Maybe we need to go to Youngstown before we come back and play Buffalo."
Buffalo (2-2) at 49ers (3-1), 1:25 p.m. CBS
49ers linebacker Aldon Smith terrorizes the Jets with two sacks and a forced fumble. Page 8
Scan: Use your smartphone to access a photo gallery from Sunday's game, or visit mercurynews.com/49ers
NFL Week 4
Packers survive call: Refs wrong Green Bay again, but it still beat Saints. Page 6
Rusty return: The regular officials are welcomed back, but they miss a few. Page 7