ST. LOUIS — Duncan Keith saw the rebound come off Corey Crawford’s body and into the slot area, so he simply wheeled and fired the puck down the ice to clear it. But the puck ticked off Andrew Shaw’s shin pads — the same magic shinpads that “scored” the game-winning goal in triple-overtime of Game 1 of the Stanley Cup Final last spring — and skittered up the ice right to Jonathan Toews, fresh over the boards and all alone at the red line.

“It was a lucky break,” Keith said. “I was happy to see it was No. 19 going on the breakaway.”

And 67 minutes into a game loaded with excruciatingly close missed chances at either end, Toews wasn’t about to squander this one. He raced in all alone on Ryan Miller, beat him with a quick deke, and gave the Blackhawks a 3-2 overtime victory over the St. Louis Blues in Game 5 of this heart-stopping first-round playoff series.

“It just happened so fast,” Toews said. “I jumped on the ice and got the puck — it just came right to me, and it happened to go in. The celebration, I just wasn’t sure if it was real or not, it happened so quick.”

Just the latest violent mood swing in a series full of them. Four of the five games have gone to overtime. All of them have come down to the wire. All of them have been wildly entertaining, and wildly tense.

The Hawks are up 3-2 in the series now, and can close it out Sunday afternoon at the United Center. But it certainly won’t be easy. While the Blues are dangerously close to a repeat of last spring’s first-round loss to Los Angeles — in which they won the first two, then lost the next four — they’ve shown the same kind of resiliency and resolve that the Hawks have shown.

“I think we got lucky on that winning goal, but I don’t think at the end of the day we win because of luck,” Keith said. “I think both teams have a lot of grit and a lot of determination, and it’s a fine line between winning and losing.”

On Friday, that fine line was the inch or so of leather that allowed a diving Corey Crawford to get a piece of T.J. Oshie’s shot into a seemingly open net on a two-on-one with Jaden Schwartz in the third period of a tied game. It might have saved the Hawks’ season, and it came late in a game in which Crawford seemed to be ailing, frequently slow to get up, and occasionally hunched over during stoppages. Hawks coach Joel Quenneville said he was fine.

“That was a huge save, that was the save of the year,” Keith said. “He was great tonight, and that save was huge.”

The Blues couldn’t capitalize on the energy created by the return of captain David Backes from the injury he suffered in Game 2 when he was laid out by Brent Seabrook. Marian Hossa scored late in the first to make it 1-0 Hawks.

Oshie tied it in spectacular fashion in the second, but Ben Smith scored six minutes later to make it 2-1 Hawks going into the final period.

The Hawks didn’t give up any late-period goals this time, but they couldn’t prevent an early period goal in the third, as Alex Pietrangelo scored at 1:42 of the third period to make it 2-2. That’s when Crawford came up huge, which allowed Keith, Toews and Shaw’s trusty shinpad to take advantage of a fortuitous bounce, and push the Blues to the brink.

“It’s done a lot for me in my career, so I owe it a lot,” Shaw said.

Email: mlazerus@suntimes.com

Twitter: @marklazerus