NEW YORK — The Boston Celtics never let this develop into the intriguing series that was expected.

Instead, they turned it into the easiest one their current group has ever experienced.

Kevin Garnett had 26 points and 10 rebounds, Rajon Rondo added 21 points and 12 assists, and the Celtics swept their way into the Eastern Conference semifinals, holding on for a 101-89 victory over the New York Knicks on Sunday.

Ray Allen and reserve Glen Davis each added 14 points for the Celtics, the first team into the second round after sweeping a series for the first time since a 3-0 victory over Indiana in 1992, the last series victory for their old Big Three before Larry Bird retired.

“It’s what we expected coming in. We knew it wasn’t going to be easy, obviously Games 1 and 2, but we found a way to put it away,” Rondo said. “We haven’t swept a team in a long time, so it’s good feeling.”