SANTA CLARA, Calif. -- You experience a lot of things when you play 12 seasons and nearly 200 games in the National Football League, but Seahawks offensive tackle Duane Brown had never participated in the type of insanity that transpired Monday night in Levi's Stadium. It left him elated and exhausted.

While teammates stripped and showered after a 27-24 overtime defeat of the previously undefeated 49ers, Brown sat on a folding chair in a corner of the locker room in his game pants, undershirt and cleats. While he may have been too physically tired to change after playing in a second straight overtime game, Brown was also emotionally drained from a game that was over, then not ... then over, then not ... and, finally, over.

"Man, I can't even count," he said when asked how many times he thought the outcome was decided before officially ending on Jason Myers' 42-yard field goal as the clock expired. "There were so many highs and lows, so many times when you start to feel like we got it, then they make a couple of plays and are right back in it. Then to go down to zero in overtime, I mean, it's wild."

The Seahawks (8-2) thought they had it won near the end of regulation, after Myers kicked a 46-yard field goal with 1:45 remaining to make it 24-21. However linebackers K.J. Wright and Bobby Wagner each dropped what should have been game-sealing interceptions, and Jimmy Garoppolo capitalized to drive the 49ers for the tying field goal with one second left in the fourth quarter.

The Seahawks again looked to be in a position to win at the start of overtime, when quarterback Russell Wilson drove them 61 yards to the San Francisco 14. But the MVP candidate underthrew a pass near the corner of the end zone and was intercepted for only the second time in 327 attempts this season.

Seven plays after linebacker Dre Greenlaw returned the pick 47 yards to the Seattle 49-yard line, 49ers rookie Chase McLaughlin, who had converted field goals of 43, 39 and 47 yards, missed badly left on what would have been a game-winning 47-yard attempt.

"Wildest game I've ever been a part of," Wilson said from his locker stall.

Yet, just when many in the sellout crowd of 71,404 began to prepare themselves for a tie, Wilson drove the Seahawks 40 yards in the final 1:25 -- the key play being his 18-yard scramble -- to set up the decisive field goal.

With that, the NFC West in particular and the conference, in general, was thrown up for grabs. San Francisco (8-1) could have taken a two-game lead for home-field advantage with a victory, as well as a three-game lead in the loss column for the division, but what appeared to be a fait accompli is now anyone's guess, particularly with San Francisco still to face, among others, Green Bay, Baltimore, New Orleans, the Rams, and the Seahawks again.

The loss was not shocking; defeats happen. But the way in which the 49ers went down was surprising. A San Francisco defense that was being touted as a dominant force simply could not make critical stops after being left with short fields following Garoppolo turnovers, and a Seattle defense that had come under fire for its elasticity was suddenly firm and stout. In fact, its five sacks matched their total for the previous five games, and its three takeaways was only one fewer than their total for the previous three games.

Clowney, who had five tackles, a sack, five QB hurries, a forced fumble, a fumble recovery and a touchdown, pretty much had his way with the San Francisco line, which returned both starting tackles from injury. His score late in the second quarter sparked the Seahawks, who trailed 10-0 at the time and were largely lifeless.

"Changed the momentum of the game," said 49ers coach Kyle Shanahan.

The Seahawks' two other takeaways -- one at the San Francisco 16, the other at the SF 24 -- both resulted in scores: Wilson found Jacob Hollister from 3 yards out, and Chris Carson burst through the interior of the line from the 1.

"We didn't play up to our standards," said cornerback Richard Sherman. "There were plays that were sudden changes, we were backed up, but you've got to find a way to get those stops."

It was a sobering night for Garoppolo, who was coming off his best game of the season the previous week, throwing for 317 yards and four touchdowns with no turnovers against Arizona. But with Pro Bowl tight end George Kittle out with a knee injury, and No. 1 wideout Emanuel Sanders leaving in the first half with injured ribs, Garoppolo finished 24 of 46 for 248 yards, one touchdown, one interception and two lost fumbles. He also had another interception negated by a Seattle penalty, plus those drops by Wright and Wagner.

More worrisome than the play of Garoppolo were the injuries. In addition to Kittle and Sanders being sidelined, defensive lineman Ronald Blair (knee), running back Matt Breida (ankle) and defensive lineman D.J. Jones (groin) left the game and did not return. Center Weston Richburg left with a hand injury but did return.

Even so, the 49ers had opportunities to remain unbeaten. There was an eery in the stadium that had not been experienced before. After so many down years, The Faithful, joined by band-wagoners, sent a current of electricity through the building. And for one-plus quarters it was like the championship seasons of yore, with the defense dominating and the offense operating efficiently.

And just when it seemed the Seahawks might not be ready for the primetime stage, Clowney picked up the loose football and returned it for the score. From that point it was a game of runs, with the Seahawks going up 21-10, only to have the 49ers rally to tie. And when the Seahawks regained the lead, the 49ers answered with their own field goal.

The pace left players and fans gasping for air. It was frenetic. It was fast. It was entertaining.

"It was fun," said Clowney.

"It's probably the wildest one for me," said Brown. "Looking at the magnitude of it, coming in here against an undefeated team on Monday Night Football, just the back and forth -- it was wild, man. But these are the type of games you dream about. We would love to make it a little bit easier. But to win a game on the road, in overtime, with zero left on the clock, I mean, it's a great feeling."

Follow Jim Trotter on Twitter at @JimTrotter_NFL.