What a Difference a Day Makes for Celtics The Celtics were contending with much more than rust and pregame jitters before Tuesday night’s season opener.

In fact, they had just about every other distraction imaginable on their plates.

Rajon Rondo’s agent announced Monday that contract extension talks between his client and the team’s brass were dead. Danny Ainge and Co. offered something in the range of five years, $45 million for the point guard. Bill Duffy countered with five and 55. The C’s said no, and all of Boston swore collectively as it appeared it’d have to wait another nine months to learn Rondo’s fate with the club.

This came, as Murphy’s Law would have it, just as Boston wrangled with the loss of Glen Davis. The breakout power forward, who spent the offseason shopping himself around the NBA (only to come crawling back to the negotiating table at a loss), got into a fight just two days before the season opener and broke his thumb.

Here’s the kicker: Baby got into the fight while riding in an SUV. With his drunk childhood friend. He’s going to miss six weeks after undergoing surgery Tuesday, and was suspended two games by the front office.

The Celtics, through all this, were heading into Quicken Loans Arena (where they hadn’t won a game since 2004) to face what appeared to be a beefed-up Cleveland Cavaliers squad. And for good measure, all eyes were on the man holding the key to Boston’s success in 2009-10: Kevin Garnett, and his surgically repaired knee.

The season, in other words, seemed to be off to a shaky start — well before the players even took the court.

What a difference a day, and win, makes.

The C’s upended the Cavs 95-89 in a battle that highlighted not just the Big Three, but Boston’s offseason additions as well.

Rasheed Wallace scored 12 points to lead a reserve unit that outpaced Cleveland’s backups 26-10. That difference, in fact, opened the door for the Celts, who started the game in a 19-4 hole in the early going. In came the second unit, which helped propel Boston to a six-point lead by halftime, a turnaround that had Doc Rivers singing the bench’s praises.

“The second unit saved the game for us,” he said.

The lesson? Perhaps the C’s won’t need Baby as much as they (and the Boston blogosphere) feared. Shelden Williams and Marquis Daniels both provided quality minutes, and Brian Scalabrine should be back soon from a right ankle sprain.

Garnett’s knee, more important, looked just fine. He still gimped a bit up and down the floor, but clearly has his stroke back and is mobile enough in the paint to be the same ol’ KG on defense. Heck, he played 33 minutes, posting 13 points on 5-of-10 shooting, 10 boards and three blocks.

Then Paul Pierce reminded everyone why the C’s were still contenders last year, even without Garnett and Sheed. He dropped 23 on LeBron James and Cleveland. Six of those came in the final 1:03, as The Truth nailed two big jumpers and two free throws to put a dagger in the Cavs’ comeback hopes late.

“It was a good Day 1,” Pierce said afterward. “Psychologically, you want to go into a team’s building and win, especially in a place where we haven’t won in a few years. … We know when we come here next time that we can do it again.”

Meanwhile, as Pierce and Boston’s players celebrated the win on the floor, the front office was busy upstairs trying to engineer a win of their own. Duffy, for all his talk Monday, still met with Boston executives on Tuesday night in Cleveland. The Celtics reportedly made a counteroffer, one which Duffy said has his interest.

The two sides have until Saturday to agree to terms, or Rondo will become a restricted free agent in the summer of 2010.

But if there’s one thing we learned Tuesday night, it’s that this Celtics team is above the distraction.

Despite fireworks early in the week, they got their first win in Cleveland in 12 tries. They learned they can beat the league’s elite without Davis (which they’ll need to do for at least the next six weeks). And they showed Shaquille O’Neal might not be the savior Cleveland needed after all.

Sure, it’s a long season, and much can change, but the Celtics’ win Tuesday night was much more than 1-0. It was a statement: The champs appear to be back.