BOSTON -- Boston Celtics point guard Marcus Smart and the man he essentially replaced, Rajon Rondo, often appear polar opposites on the basketball court. But for one sequence during the Celtics' game against the San Antonio Spurs on Sunday, Smart brought back some of Boston's fondest memories of the departed point guard.

The Celtics were down 12 midway through the third quarter and Smart was cheating over toward Tim Duncan as Amir Johnson blanketed the Spurs' big man on the perimeter. Johnson managed to knock the ball loose when Duncan tried to put it on the floor and Smart pounced. He initially fumbled the ball trying to advance in transition, but poked it away when Tony Parker reached to grab it. A step behind Parker at midcourt, Smart took a big stride then laid out on the parquet, diving past Parker's feet, and managed to gather the ball while sliding all the way to the free throw line. What's more, Smart had the presence of mind to find Jae Crowder trailing the play and flipped him the ball for a layup.

The play triggered immediate memories of the 2010 playoffs when Rajon Rondo had an eerily similar play against the Orlando Magic with Rondo corralling the ball at the feet of Jason Williams in nearly the identical spot (but finishing his own layup after springing to his feet).

No one will otherwise confuse Smart and Rondo. Smart is still trying to learn how to be a point guard and facilitator at the NBA level, while Rondo's defense wasn't exactly as strong as his All-Defensive awards suggested early in his career.

But Rondo had a knack for the spectacular and Smart is following in that line.

"On my mind, I was just thinking we needed the ball at the time," said Smart. "And I was able to get a hand on it, and I had the step on Parker when I dove on it. Jae was just doing what he was supposed to do. He was running the court and he never gave up. I just heard him call my name and he was there."

Smart seems to produce at least one highlight-caliber sequence each game, most often at the defensive end. Against the Raptors, he manage to connect on an off-balanced, one-foot 3-pointer while falling into the front row of the crowd.

Through three games, Smart is averaging 12 points, 3.7 assists, and 2.3 rebounds over a team-high 33.1 minutes per game. Boston's first unit has struggled to generate consistent offense, but Smart is still fifth on the team in offensive rating (94.4 points per 100 possessions when he's on the floor) and third in defensive rating (88.6). His assist-to-turnover ratio (11-to-2) ranks him in the top 10 among all NBA guards early in the season.

Smart is still learning how to create for himself and others, particularly in the pick-and-roll. Of the 67 players that have played 10 minutes per game and have at least 10 possessions as pick-and-roll ball-handlers, Smart ranks 42nd at 0.67 points per play, according to Synergy Sports data. But all of Boston's ball-handlers have struggled in that regard (even Isaiah Thomas is two spots behind Smart at 0.66 points per play finished as pick-and-roll ball-handler).

Smart's defense has been solid, but not spectacular (crafty Manu Ginobili took advantage of the young guard at times Sunday). But Smart is generating a high volume of steals (seven in three games) and that included four swipes against the Spurs.

At one point in the second quarter, Smart straight up ripped the ball away from Parker on the perimeter and drew a clear-path foul as he attempted to race the other way. In the final seconds of the first half, Smart again plucked the ball from Parker near midcourt and converted a layup at the other end. His final theft came when he managed to jump and deflect one of Parker's attempts to pass the ball across the court.

As the Celtics try to figure out their big-man rotation, it's imperative that Smart be able to run the team's first-unit offense regardless of who he is paired with. He's going to have to learn to be more aggressive in pick-and-rolls and must show the consistency he displayed with his 3-point shot over the summer to keep defenses honest on him as a shooter.

But Smart's hustle and heart are undeniable. He is making plays because he simply plays so hard. And while his offensive game is a work in progress, he's making fans take notice on a nightly basis because of his sheer defensive tenacity.