“It’s just rhythm for him. It’s not tempo. It’s not even a pace, I can’t explain what it is.” -- Doc Rivers, trying to describe Rajon Rondo

Rajon Rondo’s playoff tours de force have become legendary. Like the time he dropped 29 points, 18 rebounds and 13 assists on the Cavaliers in a must-win Game 4 back in 2010 that sparked the Celtics on their improbable run to Game 7 of the NBA finals. Rondo at his best is unexplainable. He's a sort of genetic goof foisted on the rest of the league: A 6-foot-nothing guard who can do the impossible with alarming ease, but for whom the mundane is incomprehensibly complicated.

So, it was a little surprising when a routine question about Rondo’s efficient night in Game 5 -- 13 points, 14 assists, a handful of rebounds and steals -- elicited the following reaction from Doc Rivers:

“I thought the second half was one of the best games he’s had for us this year in my opinion, because I thought it was more than just the basketball part of it,” the coach said. “His will, his leadership. We needed it. Whether he scored, I didn’t care what he did. He played with a force and he got us in our stuff. I can hear him barking at guys, demanding guys get into spots, and that’s not something he loves doing. He’s had better games statistically, but I thought what he did was huge for us because like I said, we needed somebody to lead us.”

For better and for worse, this Celtics team is still reliant on aging, injured players to try to carry a charmingly flawed collection of vagabond spare parts to whatever final destination awaits them. The Rondo era remains an open-ended question -- imagine if Danny Ainge found players who could run with him? But for this team, the relationship between coach and point guard serves as its central nervous system.

“He’s as smart of a player as I’ve ever been around,” Rivers said. “Sometimes he’s too smart, but when he’s right, he’s good. His IQ is unbelievable. It’s nice to have a guy who wants to think the game for the team. A lot of guys want to think the game for themselves. What play can I run for me? He thinks, what play works for the team.”

The Celtics often begin games in what they call random -- shorthand for letting Rondo attempt to break the code. Random is freedom. Random is trust. Random doesn’t always work, but it’s necessary.  

“I need him to just go play and then we try to figure it out during the game,” Rivers said. “We need him in random. As much as any guard in the league, he needs to be in random.”

In five games of this series, Rondo has played 200 minutes and attempted 67 shots, making 48 percent of them with 33 rebounds, 73 assists and 16 turnovers. Nowhere in that string of digits is a signature Rondo game, the kind that leaves everyone with their jaws hanging open and running to basketball-reference.com for some kind of historical perspective.

Maybe that’s the point. Perhaps what we’re seeing is the mature Rondo: The one who picks his spots, takes his time and throws in the right amount of ridiculous to keep everyone guessing as to his true intentions.

“I always think he has the best feel,” Rivers said. “He sees things on the floor that there’s no way I can see.”

In Game 3, Rondo did something no one’s ever seen him do before. He scored 13 points before registering his first assist. No one paid much attention because Kevin Garnett was feasting like a shark in chum-filled waters, but Rondo’s aggression opened up the paint for Garnett to operate.

In Game 5, Rondo took three of the first four shots and assisted on the other. Everything was on a drive to the basket. And then … nothing. At least on the surface.

He registered just four assists and one shot the rest of the half and while the Celtics were scoring points, it wasn’t in their usual manner. Greg Stiemsma of all people scored five quick baskets on simple rolls and pops. Garnett made 4-of-7 shots in the second quarter, his most vital work, and Paul Pierce added nine of his 16 points.

Behind the box score, Rondo was handling Avery Bradley’s job guarding the ball, an energy-draining task and not his favorite defensive job. “He likes to gamble, there’s no doubt about that,” Rivers said. “If he was a football coach, he’d blitz on every down.”

The pace was also off. Like a virtuoso having to play behind an inconsistent backbeat, Rondo found himself in a game slowed down by jump shots and free throws. Rivers would say later that something felt wrong.

“I don’t know what it was, we just weren’t right in the first half,” he said. “You could just feel it.”

In the past, this is where Rondo may have tuned out. Opportunities to run and create were non-existent and the Celtics were scoring, so why get in the way?

The third quarter will live forever as Brandon Bass’ biggest moment in a Celtics uniform, but the second half was really Rondo’s show. Time and again he found Bass for dunks and his favored pick and pop jumpers. He assisted on seven of their 11 field goals in the third quarter without a turnover. Then he went for the kill.

After a quick rest to start the fourth, Rondo hit three layups including a violent twisting off-the-glass running fadeaway between two larger defenders finished off from an impossible angle that only the most cunning pool hustler would dare attempt. Rondo pushed the lead from 13 to 17, allowing Rivers to take Garnett out of the game at the six-minute mark and the Celtics were never threatened. He was the closer, even if it wasn’t in so-called crunch time.

“When they broke the game open, he was the catalyst for the whole attack,” Sixers coach Doug Collins said.

Rondo took four shots in the second half, made three of them and scored seven points to go with nine assists and zero turnovers. Not one. Eight of his 10 shots in the game were at the rim and so were six of his 14 assists. In the five games this series, he’s taken half his shots at the basket and handed out 29 assists for dunks and layups. 

What we’ve seen the last three games is Rondo at his most precise and calculating. He remains a highlight waiting to happen at any moment -- witness his slip-and-slide dish to Stiemsma -- but really it’s his timing and sense of flow that has taken over. What we’ve seen is a point guard with 84 playoffs games and 14 series worth of knowledge at his disposal, and a player in command of his talent and his team.