SANTA CLARA -- In the locker room following the 49ers’ first loss of the season, veteran cornerback Richard Sherman preached to his teammates about using the 27-24 overtime loss to the Seattle Seahawks as a learning experience.

“Like Sherm said, it’s just what we needed,” 49ers rookie linebacker Dre Greenlaw said on The 49ers Insider Podcast.

The 49ers entered Monday night as the only unbeaten team in the NFL. They come out of the game with an 8-1 record, and a half-game lead over the Seahawks (8-2) in the NFC West.

“In this league, you’re never going undefeated. But at the same time, it’s a wake-up call," Greenlaw said. "It lets you know you can be beat any night. You got to bring your 'A game' every time. I think from here on out, a lot of guys are going to bring forward their best foot and play and execute and finish out the season strong.”

Greenlaw started Monday’s game in place of Kwon Alexander, who is out for the season after undergoing surgery last week to repair a torn pectoral. Greenlaw recorded eight tackles and intercepted Seahawks QB Russell Wilson in overtime.

Absolutely WILD 🤯 pic.twitter.com/Yh5yFVYWB6 — 49ers on NBCS (@NBCS49ers) November 12, 2019

The play, along with Greenlaw’s 47-yard interception return, put the 49ers’ offense in position to win the game. But the offense stalled after gaining a first down, and rookie fill-in kicker Chase McLaughlin shanked a 47-yard field goal attempt after making a kick of the same distance to force overtime on the final play of regulation.

“I knew Greenlaw was going to step in,” Alexander said. “I had no doubt about him. I saw it on his face when he first walked through the door.

“He’s been a tremendous rookie, doing everything right, working hard. He put a lot of extra film in this week and it all paid off. He got an interception. I’m proud of him. I’m happy for him. He’s a great young man.”

Greenlaw said he played with a lot of confidence because of the support he received on the field from middle linebacker Fred Warner, along with the encouragement Alexander gave him on the sideline.

“I made some mistakes, but I made some plays,” Greenlaw said. “I felt confident. I knew Fred was going to play his heart out, and he had my back. Having Kwon out there on the sideline, he brought us confidence. I felt good running around.”

Warner said Greenlaw stepped in and did as well as could be expected in taking over for Alexander.

“He honestly stepped in and did a great job,” Warner said of Greenlaw, a fifth-round pick from Arkansas. “I can’t say anything bad. Kwon is a seasoned vet, but Dre came out and played as such. He was communicating great. He got aligned.”

Warner had an exceptional game, as he recorded 10 tackles, including his first two NFL sacks. He forced a fumble that DeForest Buckner returned for a touchdown in the fourth quarter.

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What can the 49ers take from this loss?

“Just learn from our mistakes, look at yourself in the mirror and see what you could’ve done and keep moving,” Warner said.