Norris wiped away a two-run Cubs lead in the eighth inning by launching a three-run homer over the left-center-field wall off lefty James Russell, then helped complete a good ol' strike-him-out-throw-him-out double play in the ninth to guide the A's to an 8-7 series-opening victory.
It was the first game ever played by the Cubs at O.co Coliseum, where the A's lunged a half game ahead of the Rangers in the American League West with the victory -- mostly thanks to Norris, who is up to 11 career home runs, with five of them giving the A's the lead.
That mitigates the sight of his .203 season average.
"He does his best work late in games with runners in scoring position," manager Bob Melvin said. "He's gotten big hits for us since he got here last year. You get the big hits in bigger situations, those are the type of things that get you the respect of your teammates and give us confidence that when he comes up in those situations, he's going to come through."
Norris' blast on a 2-2 changeup followed equally impressive at-bats by a pair of his teammates. Josh Donaldson, having already launched a two-run homer in the first, led off the frame against Blake Parker with a base hit. Two outs later, with Russell on the mound, Josh Reddick drew a six-pitch walk, paving the way for Norris' entrance.
"I was just trying not to do too much, just barrel it and rely on my strengths and not try to get away from my approach," Norris said. "I was trying to see something over the middle, try to hit a nice line-drive single up the middle, and I got underneath it just enough to carry it out of the park.
"I thought it was going to go farther than it actually went … I saw him go back and I was like, 'No, don't catch it.' And then it finally went over."
Norris wasn't even supposed to start the game, not with righty Scott Feldman originally scheduled to go for the Cubs. But then Feldman was traded to the Orioles, and Chicago was forced to recall Chris Rusin.
"I woke up and saw they made a trade," Norris said. "I didn't know if it was a lefty. I saw the ticker on ESPN and didn't know anything about him. I came to the ballpark and saw it was a lefty and thought, 'Oh, great. I'm going to play today.'
"It was like a breath of fresh air. We've been doing the platoon thing for a while. Lefties face the righties and righties face the lefties."
"He had a great at-bat there," Griffin said. "He's always ready, always prepared and always has good at-bats. Everyone went crazy in here. A three-run homer to take the lead, that's huge. I gotta give it up to our guys today, because I obviously didn't get it done."
Griffin cruised through the first three innings before falling victim to a 32-pitch fourth frame that resulted in five runs. Two more in the sixth brought the count to seven, tying his career high, and he exited with two outs in the inning after going the distance in a two-hit shutout over the Reds last week.
He allowed a career-high 10 hits -- including two that didn't leave the infield and jumpstarted a lengthy fourth inning.
First, Starlin Castro reached on an infield hit that shortstop Adam Rosales couldn't get rid of in time. Second baseman Jed Lowrie then had trouble tracking down a shallow popup, and Alfonso Soriano had no trouble getting one past the infield, driving one over the center-field wall for a game-tying three-run homer.
One walk and one single later, Darwin Barney added on with a sacrifice fly, leading to Welington Castillo's RBI single that gave the Cubs a two-run advantage. This after home runs by Donaldson and Chris Young off Rusin had given the A's an early 3-0 lead.
"I felt fine out there," Griffin said. "They just got the big hit when they needed it. I felt like I was making good pitches, and they really didn't make hard contact that much. I'm just fortunate enough to be on a team that scores a ton of runs."
Coco Crisp tied the game with a two-run single following a costly error by Castro in the fourth, and two more Chicago runs in the sixth again altered the game, before Norris won it in the eighth.
Dan Otero, who worked a scoreless eighth, got his first big league win, while Grant Balfour picked up his 20th save of the season and 38th consecutive since last year.
Norris made it all possible.
"That's what makes us a good ballclub," Norris said. "We always pick each other up."