Series Takeaways: The play of J.O.

On the heels of the Celtics' four-game sweep of the Knicks in an Eastern Conference quarterfinal series, we examine specific areas of Boston's postseason play and how it might affect the team moving forward. In the second installment of Series Takeaways, we break down the impact of center Jermaine O'Neal:

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Jermaine O'Neal made a big impact at both ends of the court.The center position was the biggest unknown for the Celtics heading into the postseason, as questions regarding the health and potential contributions of Jermaine O'Neal surrounded him like a pack of angry bees. But over the course of a first-round sweep of the New York Knicks, O'Neal went into battle as Boston's fifth starter and promptly put the speculation, doubts, and uncertainties to rest.

O'Neal was nothing short of a defensive force in the first round for Boston, as he routinely blocked and altered shots and drew offensive fouls at crucial points in three of the four games. He finished the series having averaged 2.5 blocks per game and posted a block percentage (a figure that estimates the percent of opponent two-point field goals a player blocks) of 8.8, according to Basketball-Reference.com, which, entering Monday's play, ranked him second in the 2011 postseason to only Serge Ibaka of the Oklahoma City Thunder (9.7 percent).

O'Neal might not boast a hulking, physical presence the way Kendrick Perkins and Shaquille O'Neal do, but he's been just as good as the pair, if not better, in terms of understanding and executing defensive reads and rotations, and the Celtics reaped the benefits throughout the entire first round. Over the course of their first four playoff games, the Celtics' starters allowed just 92.5 points per 100 possessions, according to Basketball Value -- a terrific figure that would have led the league by a wide margin this season.

Consider Game 1, when O'Neal tallied four blocks, two of which came during a pivotal four-minute stretch in the third quarter in which the Celtics sliced a 12-point New York lead in half. He breathed life back into Boston through his defense, and C's coach Doc Rivers followed his gut instinct in the fourth quarter and played O'Neal over Glen Davis. The result? Another clutch defensive stand, as O'Neal -- already sporting five fouls -- slid in front of a driving Amare Stoudemire with just over two minutes to play and drew a vital charge. He followed that up by blocking a Ronny Turiaf layup attempt on New York's next possession and actually tied the game at 82 after rebounding and putting back a Paul Pierce miss when the Celtics went the other way.

The questions arose again after O'Neal tweaked his left wrist, the same wrist he tore cartilage in during the preseason. But he once again silenced his doubters with another monster defensive performance in Game 3. The Celtics embarked on a crucial 14-4 run midway through the third quarter to assume a commanding 21-point lead, and during the stretch O'Neal rejected a Carmelo Anthony shot attempt out-of-bounds (he also dove headfirst to the floor trying to save the ball), challenged a Bill Walker layup attempt at the rim that resulted in Walker being called for an offensive foul, and blocked a Jared Jeffries bid at the rim, forcing a jump ball.

In Game 4, O'Neal set a defensive tone for Boston from the outset, as on New York's very first play, he stepped in and drew a charge on Stoudemire.

O'Neal was Boston's defensive catalyst in the first round, and the Celtics will certainly need his shot-blocking and shot-altering abilities should they meet the Miami Heat in the second round of the playoffs. With the Heat sporting tenacious scorers like Dwyane Wade and LeBron James, who will attack the rim, the Celtics' defense in the paint will need to be crisp and O'Neal will find himself at the center of it all. If the first four games against the Knicks were any indication, he's ready for the challenge.

Greg Payne is a student intern for ESPNBoston.com