BOSTON - There are basketball players.
There are basketball professionals.
One day, perhaps soon, the Sixers might grow to be the latter.
The Celtics have been there for years.
In playoff games, basketball players focus most of the time. They get tired, and they try their hardest to fight through it. They often set punishing picks, and they frequently rebound with tenacity; they almost always trust in their system to score at the end of tight games.
In playoff games, basketball professionals focus every second, like it's a moon landing. They swallow fatigue, because, come July, they can rest in the Bahamas. Professionals set picks like brick walls. They pursue rebounds like lost lottery tickets. They fly through offenses with the faith of a zealot.
That was the difference Saturday night, when the professionals from Boston beat the players from Philadelphia in Game 1 of the Eastern Conference semifinals.
Beginning Monday night, that will be the difference in the series if the Sixers don't grow up faster.
That was Doug Collins' message to his wide-eyed troops Sunday:
"As you watch the tape, understand how important it is to execute and be tough and do all the things under pressure that you have to do," Collins said.
The Celtics executed.
The Celtics were tough.
The Celtics also have a recent world championship, three players with Hall of Fame credentials, the smartest coach in the business and a perfect fit at point guard.
The Sixers have a few guys who might be pretty good players as soon as they can rent a car without paying for the under-25 insurance.
None had played in a second-round game. It showed.
"There was no room for error in that game. It was a different feel," said point guard Jrue Holiday, who carried the Sixers past the Bulls in the first round. "One mistake, one missed shot could be the difference in the game."
Holiday said that only Game 6 of the series against the Bulls felt like Game 1 against the Celtics. In that series, Holiday, 21, joined veterans Andre Iguodala and Elton Brand; he grew, from player to professional.
Saturday, Holiday was 3-for-13 from the field, and spent much of the night dogging Celtics shooter Ray Allen. Holiday also covered Bulls assassin Rip Hamilton. Both constantly move.
Obviously, Holiday is exhausted.
Fatigue cannot excuse the disappearance of Lou Williams, basketball player.
Since the Bulls' collapse in Game 3, Williams is 4-for-17 in the five fourth quarters, 1-for-10 from three-point range. He was abysmal in the fourth on Saturday. He launched 53 feet worth of three-pointers, turned the ball over twice and got a shot blocked. He was the catalyst of the Celtics' comeback from eight points down with 11 minutes to play.
He might have been even worse in the fourth quarter of Game 4 against the Bulls, when he couldn't get a shot.
"They're going to put their best defender on him," Collins explained. "LeBron; Luol [Deng]. Any time he comes off screens, the big guys are going to try to trap him. Any time he runs a pick-and-roll, they're going to trap him. They're not going to give him good looks."
So . . .
"Hopefully, when he gets the attention of a double, he can move that ball and we're playing four-on-three. You can always be a factor. You don't have to be a factor just by making the shots."
Williams is doing neither. He has not grown.
"When teams send the doubles, if you're not aggressive, they win,' Williams said, sitting courtside after Sunday's light practice. "I'm not really worn down . . . You're getting a lot of attention. You've just got to push through."
He realizes it is not just him; Evan Turner, Spencer Hawes, Thaddeus Young, all pieces of the future, all have to play like it's a job.
"We had four, five bad possessions in a row under 3 minutes,'' Williams said.
"We've just got to make smarter plays late in the game. We made a lot of plays where we shot ourselves in the foot."
He might have been bleeding from the foot.
As in every game, there were moments when the Celtics were just better.
The Sixers allowed point guard Rajon Rondo to shoot his erratic and mechanical jump shot from outside of 15 feet. The Celtics accepted that. Rondo happened to make two of them in the fourth quarter. Members of the congregation, that's faith.
With 3 seconds to play, Celtics coach Doc Rivers designed a risky play that freed Rondo in the backcourt and allowed him to waste the final ticks. The play worked because of the jarring screen set by Garnett, which cost Turner two steps and a few precious brain cells.
It was a professional screen. You see that sort of thing a lot in springtime basketball.
No club is more professional than the plodding, perfectionist Spurs. They have won three of the last nine NBA titles with professionals Tim Duncan, Tony Parker and Manu Ginobili.
A close second? The plodding, perfectionist Celtics.
It's not only the Sixers who have to learn to win.
Memphis wasted a Game 7 chance against the Clippers on Sunday by playing badly late. Last year's run notwithstanding, the flawed, talented Thunder will get a lesson or two from the Lakers.
After lousy efforts from Lakers teammates Pau Gasol and Andrew Bynum in Games 5 and 6, Kobe Bryant embarrassed them into heroic efforts in Game 7. When that pair plays like professionals, the Lakers are the best team in basketball.
Bryant is a professional every night.
"You can't get that [in a film session]," Collins said. "You have to get out here on the court. You have to feel it. You've got to feel the heat. You've got to feel the fans."
Kevin Garnett, Paul Pierce, Allen, Rondo . . . all tempered.
"In the playoffs, you learn so much faster than in the regular season. Everything is more crucial. Everything here counts," Holiday said. "Every possession. Every rebound counts."
Down 1-0, it counts even more Monday night.