The hero of the moment is Marie Delarbre who scored midway through the third period ro break a 1-1 deadlock.
Rebecca Graeve got the puck at the point and made a sensational slap-pass to Delarbre by the side of the goal. She redirected the puck to perfection, beating Nadezhda Alexandrova who was expecting a shot from the point. The goal came at 9:12 and proved to be the winner.
"I was standing back door and Rebecca made a great play getting the puck to me," Delarbre said. "I didn't think; I just got my stick on the puck. It was fantastic."
The Russians almost tied the game in the final minute with Alexandrova on the bench, but Olga Sosina's shot rang off the post and stayed out.
"Sometimes you need to get lucky to win, and my post helped me out there," Harss said with a wide smile.
The Germans will play the United States at 7.30pm Thursday night for a place in the gold-medal game. Russia will now face Sweden in the 5th/6th place game.
"We seized the opportunity," Delarbre said. "Our coach gave us details to worry about, our game plan, how to think, and that helped us a lot."
The result ensures Germany of at least a fourth-place finish, making it the highest placing ever at the WW for a newly-promoted team (Switzerland was fifth in 2005) and the highest finish for Germany in any year (it finished fifth in 2013).
The performance is all the more impressive given that last year the team played in Division I and in mid-February of this year the team failed to qualify for the 2018 Olympics. "We were all pretty upset we didn't quailfy," Delarbre admitted, "but that's life. You have to keep your head up and look forward."
"We never gave up," Harss enthused. "We kept pushing and we believed in ourselves. We started off well this tournament, and kept going, and we got momentum. We had nothing to lose tonight, but Russia had all the pressure. They had to win."
The only time Germany had defeated Russia in six previous meetings was back in 2005.
Russia got on the board early, scoring at 2:36 of the opening period off two great plays. First, Alevtina Shtaryova fired a great pass from the left boards to Anna Shokhina in the slot. Shokhina then displayed great hands and patience, deking Harss and tucking the puck in behind her.
"I know my team can score goals," Harss said, "so that gives me confidence. After they scored, it felt like no big deal. It was one shot. I knew we could come back."
The Russians controlled the period but Germany never seemed overwhelmed or intimidated by the moment. In the second, the Germans came right back to tie the score and really should have had a couple of more goals to boot.
Germany had a great chance to tie early in the second when Marie Delarbre fed Nina Kamenik in the slot, but Kamenik bobbled the puck and couldn't get off a good shot.
A little while later, Iya Gavrilova had Harss beat but hit the post with her shot along the ice.
Russia incurred two early penalties in the middle 20 but killed these off despite some good pressure by the Germans. After killing a penalty of its own, Germany drew three penalties in short order resulting in two lengthy 5-on-3 situations.
The Germans didn't take long to capitalize. Julia Zorn fed Kerstin Spielberger with a soft pass that Spielberger ripped to the far side, tying the game at 14:44. But they maintained a 5-on-3 and couldn't do further damage.
Teams left the ice tied, 1-1, a score the Germans were happy with, the Russians not so much.
And then the improbable happened. Delarbre scored, and Germany is in the semi-finals.