If the Chicago Bulls were unprepared for the truth about Derrick Rose and his ruptured knee ligament after Game 1 of this opening-round series, nothing at all readied them for the terrible consequences of his absence during the third quarter of Game 2 against the 76ers on Tuesday night.

Maybe the Bulls thought they could observe a quiet mourning period for their championship hopes and still shrug off a minor obstacle like the Sixers in the process. You could hardly blame them, on several counts.

Chicago played 27 games without Rose this season and won 18 of them. It wasn't as if looking around and not seeing Rose was that much of a shock. As for the Sixers, going into Tuesday night, it would have been hard to predict a sudden rekindling of their early-season success. The Sixers were 15-23 since Feb. 15 on merit, a disjointed, mismatched team that had bench players starting, starters on the bench, and usually lacked the perimeter shooting that makes opponents play honest defense.

The Bulls, particularly after walking through the first half with little resistance on the way to a 55-47 lead, were taking the outcome of the game and the series for granted when the third quarter began and the Sixers suddenly rechanneled their inner January.

Defense at the NBA level isn't really skill, because everyone has skill. It is effort and the willingness to work hard at the end of the court that doesn't usually make the highlight reel. The genius of what Doug Collins has been able to do with the Sixers since his arrival really lies in his ability to extract that effort from a team that, deep down, knows it is not among the league's talented elite.

On many NBA teams in a similar circumstance, players will be asked for that effort and they will respond, at least to themselves, "What's the point?" It is a reasonable question in some ways. Beating one's head against a wall of greater talent isn't any fun. So you play pretty hard, take your shots at the other end and, if they fall, maybe you win.

Collins knows that the answer to the question for the Sixers, the point of why that effort has to be given, is that the shots will never fall often enough for them. The Sixers have a word to describe beautiful, flowing games in which both teams are able to display the natural rhythms of their offenses: losses.

"We're not a great half-court team. We don't have great post presence," Collins said. "When we're good is when we get in the open court . . . points off turnovers, fastbreak points . . . that's where we really thrive."

That is where the effort pays off and it is what rang the cash register in the third quarter Tuesday night. Without warning, the Sixers were all over the court on defense and the Bulls reeled backward in shock and never recovered. It must have been a pretty good halftime speech.

In the first seven minutes of the third quarter, the Sixers forced turnovers, hectored Chicago into bad shots, got a couple of blocks, and rebounded everything. They used those defensive stops to ignite their running game and go on a 21-6 spree that withered the Bulls' will to keep fighting through the confusion.

The question isn't what happened in Game 2. That much was obvious. The question is what will happen next, and only the Chicago Bulls can answer that. The Sixers will continue to do what they do, and now they have the added motivation of seeing it work on a postseason stage.

The Bulls, however, can go two different ways. They can respond to the double blow of losing Rose and then Game 2, or they can shrug and pack it in.

Legendary coach Chuck Daly always said you can't fool "dogs, kids, and NBA players," and the Bulls are very aware that without Rose they will not be getting out of the Eastern Conference playoffs this season. It is now a matter of how far they get and how much heart they are willing to display in the interim.

Can they beat the Sixers without Rose? Of course. Happened on March 17, actually, with backup point guard C.J. Watson leading the Bulls with 20 points. Unlike Tuesday's game, the Bulls won that one at the free-throw line and on the glass. It was an effort game dominated by Chicago's play in the basket area, particularly by Luol Deng and Joakim Noah.

With the same effort, Chicago would be likely to get the same result. The Bulls are still a very good team. But convincing opponents that the effort isn't worth it is the singular specialty of the Sixers. They are annoying to play against when the defense is really cranking.

That is where the Sixers are right now. Where the Bulls are is anyone's guess.

The Sixers come home having thrown a punch that landed hard. They wait now to see if there will be one coming in return.