There was a discernible difference between the Rajon Rondo who started sluggishly in last night's 95-90 loss to the Orlando Magic in Game 1 of Eastern Conference semifinals and the Rajon Rondo who finished the game with a flurry, scoring 12 of his 14 points in the second half.
"When we have Rondo it's a whole different ballgame," said Glen Davis. "You can tell the difference in the game when Rondo's attacking and finding people. He's the key to our team. When we have him, it's tough to beat us."
Last night, however, the Celtics proved to be vulnerable after Rondo shot 1 for 7 in the first half. He airballed one of his patented lane floaters, which concerned not only Celtics coach Doc Rivers but also the TD Banknorth Garden crowd of 18,624.
"There was a point, I don't know, about four minutes gone in the third, he tried to shoot that floater and missed it," Rivers said. "I called him over and I said, 'Rondo, you're not playing with speed.' And I thought after that his speed became a factor. It's tough to make a floater when you're walking. And he was trying to read the defenses instead of playing with his instincts.
"And I thought once he played with his instincts and played with his speed, his speed is power. That allowed him to be a better player. And I thought that changed the game for us, once he got it going."
Asked if he was fatigued after going to the limit to close out the Bulls in an epic seven-game first-round series, Rondo replied, flatly, "No."
"There was no fatigue," Rivers said. "I don't believe in that. We had a whole day off, we ain't making no excuses.
"Obviously I've got to do something to get them going better."
Rondo's sluggish start had repercussions. The Celtics were unable to respond when the Magic turned a 24-19 lead into a whopping 18-point lead at the break, 54-36, which grew to as many as 28 when J.J. Redick knocked down a 3-pointer to make it 65-37 with 8:58 remaining in the third quarter.
"I just wasn't aggressive," said Rondo, who finished two assists shy of a triple-double (eight of his 10 rebounds came in the second half). "I usually get the rebounds myself and push it, but we were taking it out of the net every time and it was hard to get aggressive in the open court in transition. We were taking the ball out of bounds every time in the first half."
That was mostly the result of the Magic's dominance in the paint, where Dwight Howard (16 points, 22 rebounds) helped Orlando outscore Boston, 30-16, in the first half and 42-22 overall.
"We had our opportunities and we had our chances," Rondo said, referring to a run that pulled the Celtics within 82-73. Over the next five minutes, however, the Celtics struggled to score until Rondo stole the ball from Rafer Alston at midcourt and found Brian Scalabrine for a 3-pointer that made it 89-80 with 3:17 to go.
After Davis came down with a Hedo Turkoglu miss, Rondo made a dribble-drive penetration before kicking it out to Paul Pierce for another trey that pulled the Celtics within 89-83 with 2:42 left.
"We just have to get off to a good start," Rondo said, when asked what lessons he would take into Game 2 tomorrow night. "I don't think we had the lead or anything in the first quarter, but we can't dig a hole like we did and get down by 28 points."
Michael Vega can be reached at vega@globe.com. 
