LeBron James, right, was harassed all through Game 1 by Paul Pierce and the stingy Celtics. ((Jesse D. Garrabrant/NBAE via Getty Images))

The underdog Cleveland Cavaliers nearly pulled off a surprising win over the mighty Boston Celtics on Tuesday night. Even more surprising, they did so despite a horrific performance by their best player.

Though they harassed LeBron James into 2-of-18 shooting and 10 turnovers, the Celtics needed a clutch basket from their own leader, Kevin Garnett, in order to eke out a bruising 76-72 home victory in Game 1 of what could become a hotly contested second-round NBA playoff matchup.

"This was two heavyweights, just body-punching," said Garnett, whose 28 points included a key hoop in the final seconds that made up for an off night for the rest of Boston's Big Three. "There was no finesse, no jabs, just an all-out, beat-down, defensive fight."

With the Celts' vaunted defence frustrating him with a combination of double teams, traps and plain old rough treatment, James made the first field goal of the game then didn't score another until less than six minutes remained in the fourth quarter. Still, he nearly recorded a triple-double, finishing with 12 points thanks to an 8-of-10 performance from the line while dishing out nine assists and grabbing nine rebounds.

"I missed a lot of shots I know I can make," James said, staring at the stat sheet incredulously after scoring just two points in the second half and missing his last six shots in all. "I missed layups. Those layups I've made my whole life."

Cavs shut down two of Big 3

Even with their star player suffering through one of his worst nights in recent memory, the Cavs found themselves in a 72-72 tie after top scorer Zydrunas Ilgauskas (22 points, 12 rebounds) tipped in a failed James drive with half a minute left in the fourth quarter.

But Garnett responded with a successful drive to the basket to restore Boston's lead. After James missed another driving layup, James Posey nailed a pair of clutch free throws with 8.5 seconds left to give the Celtics an all-but-insurmountable four-point advantage.

Rajon Rondo had 15 points and six assists for Boston, while veteran reserve Sam Cassell finished with 13 points. The point guard tandem provided the strongest complement to Garnett, who placed third in the NBA MVP voting announced Tuesday, behind winner Kobe Bryant and runner-up Chris Paul. James finished fourth.

Though they couldn't control Garnett, the Cavs excelled at shutting down the other two members of the Big Three that led Boston to the NBA's best regular-season record. Paul Pierce managed just four points on 2-of-14 shooting, while Ray Allen posted a goose egg, missing all four of his attempts from the field.

"Me and Ray, we figure if we play [James] to a standstill … we give ourselves the best chance," Pierce said. "He is not going to go 2-for-18 every game but, hey, we're going to do our best to try  to make him."

Game 2 is set for Thursday night in Boston, before the series shifts to Cleveland for Games 3 and 4.