The result was an 82-75 loss for Boston before a raucous crowd at the Wells Fargo Center, and a seventh game in this Eastern Conference semifinal.
The Celtics' offense was lethargic throughout the night. The visitors made just 33.3 percent of their shots from the field, and hit only three three-point baskets in 14 attempts. The Celtics had just 14 assists on the night, or roughly Rondo's average.
Boston coach Doc Rivers bemoaned the fact that his team had "a lot of empty possessions offensively." And he felt Rondo couldn't decide whether to be a facilitator or a scorer.
"I don't know - I think he wanted to play well," Rivers said. "I thought he attacked early and missed some shots. He probably got caught in-between himself.
"He saw that the offense wasn't working, so I thought he was kind of trying to orchestrate the offense and trying to go, and he probably got caught in the middle tonight. It happens. He'll be better."
Rondo scored only nine points, shooting 4 of 14 from the floor, and grabbed nine rebounds to go with his six assists.
Through five games, only Magic Johnson (1985) had accounted for 13 or more assists in the first five games of a playoff series besides Rondo.
But Rondo was strangely silent Wednesday night.
Some of it was the Sixers, led by Evan Turner, who guarded Rondo for much of the night, trying to keep him from driving to the basket, but there were times Rondo just didn't look interested in going to the hole.
With one minute left until intermission Wednesday night, he had just one assist and the Celtics were shooting less than 30 percent from the field, looking as if they needed a spark.
But then Rondo set up Kevin Garnett for a 12-footer to give the Celtics the lead. After Turner answered for the Sixers, Rondo drove the lane and kicked the basketball to Mickael Pietrus in the left corner, and Pietrus swished a three-ball with a half-second to play, allowing Boston to enter the locker room with the lead.
In the third quarter, Rondo converted three of the Celtics' six field goals - two on baskets off offensive rebounds. He had one assist, a pick-and-pop basket by Garnett, which has been a staple of the Boston offense the entire series. But Rivers didn't care much for the offensive flow his team showed all night.
"We've got to do a better job offensively," he said. "I thought we had a lot of empty possessions offensively. We played in random a lot tonight. We really never established Kevin, even though Kevin had points, it was the type of points that we needed. We have to do a better job there."
Boston got to within six points with less than two minutes to play. But Rondo lost a defensive rebound out of bounds on a Sixers possession.
It turned out neither he nor his team to could get to the level they needed to close out this series in six, and now the Celtics will have to play one more game.
Contact Joe Juliano at 215-854-4494 or firstname.lastname@example.org or follow on Twitter @joejulesinq.