"It was huge," Butler said. "It's big to come in here and get a win on the road."
Ginobili joined San Antonio's growing injury list Tuesday night, straining his left hamstring against Houston after throwing down a one-handed dunk.
Spurs coach Gregg Popovich dismissed any talk of fatigue.
"I don't care, that's just an excuse," Popovich said. "Everybody tried as hard as they could. I don't know how to measure fatigue. Just go play. We try to watch people's minutes and that kind of thing.
"It doesn't matter who's hurt, or what your schedule is, or anything like that. You go play. Nobody cares. All that matters is the win or the loss. We lost our defensive consistency and they went up."
The Bulls can certainly relate after losing All-Star point guard Derrick Rose to a season-ending knee injury.
The Bulls have attempted to step up collectively since the injury and that depth led them to their 10th road victory of the season.
"We have a roster full of NBA players just like everybody else," Butler said. "A lot of people sleep on us, but we have a really talented group of guys that do so many things well. When we play together and just as hard as we can, I think we can win a lot of games."
With four players missing from their main rotation, the Spurs turned to their depth with less effectiveness.
Nando De Colo and newly signed Othyus Jeffers, who both played in the D League, both started for the first time this season. Jeffers brought hustle and De Colo another distributor, but neither brought much offense. Jeffers failed to score, going 0 for 1 from the field, and De Colo had eight points.
It led to a disjointed and inconsistent offense for San Antonio. The Spurs had 19 turnovers and only 16 assists on their 33 field goals.
"It's tough to keep a rhythm," Duncan said. "With a lot of our guys out, our consistency just isn't there on both ends. We can't sustain for the periods of time that we need to.
"But at various points throughout the game, we're where we want to be. And then we go through lulls where defense or offense can't get it done."
San Antonio went scoreless for nearly five minutes as part of Chicago's 12-5 run to close the first quarter. It could have been worse, but Patty Mills made a 3-pointer with 2.8 seconds remaining to keep the Spurs within 21-15.
San Antonio responded with a 17-3 run to take a 27-24 lead. Chicago scored just seven points in 10 minutes bridging the first and second quarters, turning a 21-12 lead into a 36-28 deficit.
But the second half belonged to the Bulls and Butler.
"It's just tough right now," Parker said. "Back to back, it felt like we had no energy. We didn't make shots in the first half. We had some pretty good looks in the first half; open 3s. They just didn't go in and we just try to fight through it. We tried to get some energy in the second half, but they played better than us."
Butler was 7 for 11 from the field as the Spurs had no answer for the athletic forward.
"Jimmy was terrific," Bulls coach Tom Thibodeau said, "with his defense and then turned that defense into offense, which was a big plus for us."
Not having to guard Ginobili, Leonard or Green on the wings allowed Butler to defend Parker and the other Spurs guards.
Parker finished 8 for 17 with six assists in 34 minutes.
"It's a challenge (defending Parker)," Butler said. "He can do so many things well, but whenever I was beat, I had Taj (Gibson), (Nazr) Mohammed, Jo (Noah) or Booz (Boozer) to alter his shot or make him go a different direction."
Green (fractured left index finger), Leonard (fractured right fourth metacarpal) and Splitter (sprained right shoulder) all sat behind the bench during the game, all wearing sport coats with no ties. Ginobili was not with the team. ... Noah (illness) and Kirk Hinrich (right hamstring) both played after being game-time decisions due to injury. ... Jeffers endeared himself to the fans and Spurs quickly, diving onto court twice on the same possession for a loose ball, earning a jump ball. ... Noah was given a technical foul with 5:02 remaining in the third by official Josh Tiven. As he ran back defensively, Noah punched the air in disgust after missing a layup he thought was caused by a foul on Duncan. ... When asked how the Spurs will handle the rash of recent injuries, coach Gregg Popovich said he didn't want to be a smart-(aleck) but ... "You play the guys on the bench. We can't play the guys on the other team. I know that."