It's on to the LeBrons.

Now, the playoffs really start, and we get to see just how good the Boston Celtics are and whether their underachieving regular season was playoff prologue or the epilogue to the end of the Big Three era.

Before this season started no one was using the Miami Heat as the measuring stick for Doc Rivers and the gang. While 70 wins was unrealistic, so was expecting the Celtics to be challenged in the first round of the playoffs by Dwyane Wade and a bunch of Tito Jacksons, as Wade's cell phone commercial comrade Charles Barkley referred to Wade's "supporting" cast earlier this season. It's safe to say that Michael Beasley and Jermaine O'Neal are not in Wade's Fave Five.

In some ways this was a no-win series for the Celtics, because there was nothing they could do against the Heat to prove that they're completely back to the team that opened the season 23-5. That's not their fault. However, the Celtics boosted confidence in their contender credentials by finishing off the Heat in five games, and it would have been a sweep if not for Wade's 46-point virtuoso turn on Sunday.

But projecting the progeny of the parquet against LeBron James and the Cavaliers is a whole different deal, folks.

Miami was a great matchup for the Celtics because they didn't have a low-post presence or a versatile, athletic power forward who can extend a defense from the perimeter and force Kevin Garnett to step out and defend. Those are two areas that really test the Celtics' defense, and the knee of KG, who averaged 15.8 points and 8.8 rebounds in this series and looked as healthy as he has since the start of the season. Unfortunately for the Celtics, those are two things that the Cavaliers have at their disposal, with Shaquille O'Neal at center and Antawn Jamison at the four.

Miami players not named Dwyane Wade shot a collective 38.4 percent from the field in the Eastern Conference first-round series. James will have a lot more help than that.

"It's going to be similar to Miami with a better cast," acknowledged Garnett. "They are playing great as a unit. Shaq seems to be thinner and fit. ... He looks very sharp."

So, do the Celtics. The 30-something Big Three of Garnett, Paul Pierce and Ray Allen appear to be clicking on all cylinders at just the right time, and the Celtics defense might not resemble the '85 Bears, but at least it doesn't look like a slam-dunk contest is being held in the lane any more.

Pierce is back to elite scorer form again (19.6 points per game), and any questions about his health had to be answered by the fact he logged 46 minutes in the close-out contest, the most of any player.

Garnett was active on the boards, got to the free-throw line, and his step-out, face-up jumper was on the mark.

The ageless Allen made Danny Ainge look like a genius for not parting with him at the trade deadline. I was wrong, Ray, forgive me.

Despite having the Sisyphean task of defending D-Wade, he was actually the team's second-leading scorer against Miami (19.4 points per game) and shot a scorching 52.4 percent from the field. Allen was even better from beyond the arc, shooting 52.8 percent.

Allen changed the game last night with a 20-point second half (on 7 of 9 shooting) that started with a barrage of three 3-pointers in the third quarter in a span of 1:58 that helped the Celtics open up a 21-point lead. When the Heat cut the lead to three early in the fourth, Allen responded with a conventional 3-point play.

The Cleveland series may hinge not on the Big Three, but on their dynamic little point guard, Rajon Rondo.

Next to LeBron, Rondo is the most indispensable player in the Boston-Cleveland series. Proof of the latter, is that he averaged 42 minutes per game against Miami. Rondo fared well against the Cavs this season, averaging 14.8 points and 10.3 assists, both higher than his season averages. He'll have to fare even better for the Celtics to precipitate an early start to the Summer of LeBron.

Rondo came out in attack mode from the opening tip last night. He had had 8 points, 4 rebounds and two assists in the first quarter, and stuffed the stat sheet with 16 points, 12 assists, 8 rebounds, 4 steals and one indomitable will to win.

You have to love the fact that Rondo doesn't defer to anyone in the NBA, whether it's Kobe Bryant, Chris Paul or Wade, whom he woofed at last night heading into a timeout, shortly after trying to elevate over D-Wade only to have his shot blocked.

"Anytime Rondo is aggressive like that like you said it sets the tone for pretty much how we are going to be," said Garnett.

The biggest bugaboo in Rondo's game -- free-throw shooting -- has not been a problem in the playoffs. After shooting 62 percent during the regular season, Rondo made 83 percent of his freebies against the Heat.

Essentially, what the Celtics have been presented is a do-over of the 2009 playoffs, but with Garnett a go and Cleveland standing in for Orlando. The team is virtually identical because the additions of Rasheed Wallace, Marquis Daniels, and Nate Robinson have had no impact.

Last year, the Celtics were ousted in the second round by Orlando in seven games. If that happens at the hands of Cleveland this year, then their run has run its course, and they're the 1991 Detroit Pistons, who coincidentally went 50-32, to LeBron's Michael Jordan.

We were hard on the Celtics because we expected so much of them, but now they're in a position to finally fulfill those expectations.

Bring on LeBron.