You saw the difference Tuesday night at American Airlines Center between a pretty good team that's going to make the playoffs, and a team such as the Miami Heat, who have championship aspirations.
In the process, you saw exactly why the Dallas Mavericks will be a nuisance to some higher seed in the playoffs, but why they're not built to make a long playoff run.
Miami 117, Dallas 106.
Understand, the Mavs played as hard as they could against the Heat. They outrebounded the smaller Heat by 22 and made 10 more free throws.
And when Vince Carter converted a four-point play with 7:47 left in the fourth quarter, the throng of bandwagon Heat fans wearing their red-and-black jerseys and matching flat-bill caps were awfully quiet.
But the Heat did what all legitimate title contenders do at winning time: They turned up the defense and stopped the Mavs' offense.
First, Miami forced a couple of turnovers; then they harassed the Mavs into missing contested shots.
Dallas made only 4 of 19 shots in the fourth quarter. See, the Mavs can't do that.
Oh, they can score with any team in the league, and Dirk provided a star performance with 22 points, nine rebounds and seven assists. Four other players also scored in double figures.
But these Mavs can't stop anybody the way Miami shut down Dallas in the fourth quarter -- at least they can't do it consistently.
James made consecutive 3-point baskets, threw down a vicious dunk, hit a couple of free throws, made a layup and assisted on a dunk during during a 16-1 run that gave Miami a 108-96 lead with 2:14 left.
James finished with a season-high 42 points after making 16 of 23 shots, including 4 of 8 3-point attempts. He also had nine rebounds and six assists.
Miami shot 57.1 percent from the field. Nowitzki, Ellis and Calderon can play as hard as they want to, but they're average defensive players most nights.
When their concentration wanes and the rest of the team has mental lapses, then their deficiencies are magnified.
"We played extremely hard and our heart was in the right place all night," said coach Rick Carlisle, "We just had some untimely turnovers, some untimely misses and that really hurt us.
"They are a team that takes advantage of those and they make you pay an exponential price. That's what happened in the fourth quarter."
The Mavs remain eighth in the Western Conference and they should make the playoffs without too much stress.
Listening to owner Mark Cuban before the game, a trade for an impact player this week at the NBA trade deadline seems remote at best. The Mavs aren't interested in giving up draft picks and most teams aren't moving their stars.