Chicago led 7-5 after 7 1/2 innings, and Russell got ahead, 0-2, in the count, but Norris belted his fourth home run for the game-winner. Russell is now 0-for-6 in save situations.
"He can't get really anything down in the strike zone," Cubs manager Dale Sveum said. "His changeup is either short or hung, and can't spot a fastball down and away. It's basically just no location. The confidence probably isn't too good right now."
It's the Cubs' 17th blown save, most in the Major Leagues.
"I didn't make a good pitch when I needed to and paid for it," Russell said. "I just have to get the ball down, it's that simple. It's not that difficult. It's that one thing, get the ball down and that won't happen."
It obviously isn't the first time the Cubs have blown a lead this season. They now have lost 25 games in which they've led at some point.
"It's almost comical to see this happen every single night," Sveum said. "We have the lead and get beat by guys who sometimes hardly even hit home runs. [Norris] had one at-bat off a left-hander in 15 days and beats us with a three-run homer."
Norris thought he'd be facing a right-hander.
"I was a little in awe when they didn't make the change, because obviously my splits are a little bit favored to the left-handed pitchers so far this year, and when they didn't I just told myself don't miss it if you get it, and fortunately I got a good pitch to hit -- at least I thought it was," he said. "These guys were saying it wasn't, but I made the most of what he gave me."
Alfonso Soriano hit a three-run homer and Welington Castillo hit an RBI single and a tiebreaking two-run double for the Cubs, who were making their first regular-season trip to O.co Coliseum. They're now 10-5 in Interleague Play.
"We played good, but we didn't play good enough to win this game," Soriano said. "I hope tomorrow we have a better chance to win the game."
Chris Rusin started in place of Scott Feldman, who was dealt to the Orioles earlier in the day for pitchers Pedro Strop and Jake Arrieta in a flurry of roster moves. It's the reality of being 11 games under .500.
"We have three teams in our division with the three best records in the National League, or close to it," Cubs general manager Jed Hoyer said. "I think, realistically, our chances of playing in October are small. We need to add a lot of talent to get better for the future.
"Players should be trying to win every single game, that's the nature of their job," Hoyer said. "I would expect the players to look at it that way."
Was Sveum worried about any kind of letdown following the deals?
"I'm not concerned about that," Sveum said. "We're still viable and able to fill those roles now. If you start getting more thin, then things change. I'm not worried. They're professional players and they have to go out and perform."
Soriano saw the changes last July. His reaction to Tuesday's deal?
"It's part of the game," Soriano said. "The front office, they know what they're doing. I just try to do my job. I let the front office take care of business and I try to take care of my business in the field. The front office, they know what they're doing and they're doing what's best for the organization."
The A's weren't very hospitable. Josh Donaldson hit a two-run homer in the first, and Chris Young added a leadoff homer in the second for a 3-0 lead.
Soriano delivered in the fourth against A.J. Griffin. Starlin Castro and Nate Schierholtz both singled to set up Soriano's 10th long ball of the season and No. 382 of his career. He's now tied with Frank Howard and Jim Rice for 61st on the all-time home runs list. In his last six games, Soriano has four doubles, one triple, three home runs and eight RBIs.
"I'm feeling good now," the 37-year-old outfielder said. "It's never too late, and I feel I found my swing, and now I feel comfortable at home plate."
Darwin Barney hit a sacrifice fly and Castillo added an RBI single in the fourth to go ahead, 5-3.
Rusin, starting on three days' rest, was lifted after getting Josh Reddick to ground out to start the fourth. Carlos Villanueva walked Norris, and pinch-hitter Eric Sogard was safe on an error by Castro, who nearly collided with Soriano in shallow left chasing a popup. Both runners scored on Coco Crisp's single to tie the game.
"The [play in the fourth], 'Sori' lost in the twilight and called it real late, and it obviously cost us two runs," Sveum said. "It's unfortunate it ended up being two runs because of that."
The Cubs had two on and one out in the sixth, and both scored on Castillo's double to center. Castillo was thrown out trying to stretch his hit into a triple.
Luis Valbuena led off the ninth with a walk, but was thrown out at second as Castro struck out.
"You're trying to stay out of a double play and make something happen, and once again, we didn't perform and swung right through a fastball," Sveum said.
The Cubs are at the halfway point of the season, and can expect more roster moves as the Trade Deadline approaches. They've had plenty to deal with on the field.
"You go to sleep and start a new day," Russell said. "The sun will rise and that's the thing about baseball -- you get your butt kicked one night and you get to wake up and do the same thing all over again. You've got to put it behind you and keep going."