SANTA CLARA, Calif. >> Brock Purdy and the San Francisco 49ers seemed poised for another fast start when two big passes to George Kittle moved them into the red zone on the opening drive of the game.

What happened next set the tone for the rest of the game.

Purdy threw an interception to Kyle Hamilton in the end zone to thwart the drive and then kept giving the ball away in the worst performance of his career, sending the 49ers to a 33-19 loss to the Baltimore Ravens on Monday night.

“I have to look myself in the mirror and ask myself why or how that happened and why I made those decisions,” Purdy said. “Our team came ready to play and for me to make some decisions like that, it pains me. It’s not fair to these guys. I have to realize that and understand that, and I have to get better for my team.”

Purdy threw three more interceptions on the next six possessions to become the first 49ers player with four in a game since Colin Kaepernick in 2015. Purdy didn’t produce a TD — either running or passing — for the first time in 20 career starts and looked overmatched against Baltimore’s stellar defense.

He finished 18 for 32 for 255 yards before leaving with a stinger late in the game that isn’t considered serious. But his performance looked much more like a player picked in the seventh round a year ago than one who came into the game as the favorite to win MVP.

“I didn’t mind his demeanor,” coach Kyle Shanahan said. “He stayed in there and kept battling. Our whole team struggled there in the second half, so it wasn’t just him.”

Purdy was far from the only problem for the 49ers, who came into the game as the NFL’s most complete team but got dominated in all phases of the game.

The offense kept giving the ball away and produced only two scoring drives until Sam Darnold threw a late touchdown with San Francisco trailing by 21 points.

The defense couldn’t keep up with Lamar Jackson, who beat them by running as well as extending plays to hit big passes in a turnover-free performance.

Even the special teams had issues, allowing a big punt return followed by a personal foul on punter Mitch Wishnowsky to set up one TD drive.

“Mixed emotions about it, honestly,” linebacker Fred Warner said. “We know the recipe for winning football games for our team. We’ve got to take the ball away on defense. We didn’t take the ball away. We’ve got to protect the ball on offense. We gave it away. So when you do that, that’s how you lose games.”

Despite the loss, the Niners are in a three-way tie with Philadelphia and Detroit for the best record in the NFC and can still clinch the No. 1 seed and a first-round bye with wins in their final two games.

They finish the season with games at Washington on Sunday and at home in Week 18 against the Rams.

“Our guys are real disappointed tonight,” Shanahan said. “They should be. But when it comes down to it, we’re still in the same situation that we were before the game started. We’ve got to take care of our business.”