"They're a good team," Rusin said. "I was fortunate enough to keep the ball low, keep it moving and keep them off balance."
The loss, combined with the Dodgers' victory, knocked the D-backs out of first place in the National League West for the first time since May 17. They trail Los Angeles by a half-game.
"There's a long way to go in the season," D-backs manager Kirk Gibson said. "I don't think you can change the way you're doing things. We're trying to play good ballgames. We're trying to make good plays. We're trying to swing the bat and pitch as good as we can. There's a long way to go. This doesn't mean we're out of it by any means."
No, but it does mean one thing: The D-backs need to start playing better sooner rather than later.
On June 21, the Dodgers were in last place and trailed the D-backs by 9 1/2 games. The Dodgers have gone 21-5 since, while the D-backs have gone 11-15, causing a 10-game swing in the standings in one month.
"They've been playing better than us," D-backs catcher Miguel Montero said. "They are where they are because they've been winning ballgames and we've been losing ballgames, so we can't really worry about them. We've got to worry about us and winning ballgames."
If the D-backs are going to do that, they'll have to find a way to get their offense going.
Arizona has scored eight runs in four games since the All-Star break.
"I've been through many of these as a player and as a coach and a manager," Gibson said of the offensive slump. "The guys are working hard on it. Things aren't coming very easy for us. The guys are hustling. That's just the way the game goes sometimes. It's not like we're out there loafing around. They are frustrated, yes, but they played their hearts out."
Tyler Skaggs, who was sent to Class A Visalia during the All-Star break so he could remain on schedule, returned to Arizona and put together a quality start, but two mistake pitches led to two home runs, and that was the difference.
The Cubs took a 1-0 lead in the second on a homer by Dioner Navarro, who was hit by a Skaggs pitch in his next at-bat and warnings were issued to both teams by home-plate umpire Doug Eddings, though neither side seemed to believe it was intentional.
The Cubs once again used the long ball in the fifth, increasing their lead to 3-0 when Junior Lake blasted a two-run homer to left-center.
"I left a few up in the zone," Skaggs said. "A few pitches weren't where I wanted them to be, and they got hit out of the yard."
Skaggs finished with three runs allowed on seven hits with six strikeouts in six innings, while Rusin held the D-backs to just one hit through the first five innings.
"I'm going to give credit to him because I think he threw the ball good," Montero said of Rusin. "But I think we should have hit him. We had good pitches to hit and we never did. I think it's just disappointing that we couldn't help Tyler."
The D-backs broke through in the sixth inning with a pair of runs to cut the Chicago lead to 3-2, but they failed to take advantage of scoring opportunities in the seventh and eighth.
In the seventh, the D-backs loaded the bases with one out, but Eaton and pinch-hitter Eric Chavez both flied out to center. Goldschmidt singled with one out in the eighth and advanced to third with two outs in the frame, but Montero struck out to end the inning.