BOSTON -- Doc Rivers was 34 years old during his final NBA playing season, so immediately he admits the comparison is apples to oranges. But asked to explain where Shaquille O'Neal found the effort to put the Boston Celtics on his 38-year-old back in the fourth quarter of Wednesday's 86-82 triumph over the Detroit Pistons at the TD Garden, Rivers could only reflect on his final season in San Antonio.
"Listen, all I can reach back to is my last year, which is not even close," Rivers said. "But honest to God, when you get old, there are days the legs work and days they don't. And you can't call them. Honest to God, in my last year, there was no rhyme or reason. You can play a back-to-back game, the second day, and you felt great, and the first [you didn't] -- it made no sense. I think that's who he will be."
Over the past three games, Shaq has turned back the clock and, with the girth of his 7-foot-1, 325-pound frame, is preventing it from spinning back to the present. O'Neal scored 23 points on 10-of-12 shooting over a season-high 35 minutes in Friday's win over Charlotte, then battled through foul trouble to chip in 12 points on 5-of-7 shooting in Monday's playoff-like triumph over Dwight Howard and the Orlando Magic.
On Wednesday, O'Neal was as quiet as his fellow starters while connecting on just two of his first five shots for five points over the first three quarters. He then exploded for seven points in the final frame, adding three rebounds and two steals as Boston erased an eight-point deficit to emerge with a win it probably didn't deserve.
O'Neal finished with 12 points and a season-high 12 rebounds over 25 minutes. He was the crunch-time center until Detroit dusted off the Hack-a-Shaq defense, which forced Rivers to insert Glen Davis over the final 1:28.
"The whole team was flat; I just had to pick it up," O'Neal said. "I'm not really playing a lot of minutes. I'm not really tired. We haven't been rebounding that well, so I wanted to try to get every loose ball, every rebound, and when I got back in in the fourth quarter, we were down [eight], so we just had to try to get everybody involved."
There was Shaq, scoring all seven of his fourth-quarter points in a dizzying 1:45 span, highlighting a 9-1 run that tied the game at 76 with 5:07 to play.
A quarter earlier, O'Neal registered both of his blocks, nearly pancaking Rodney Stuckey while falling out of bounds after rejecting his baseline drive early in the third frame. Less than two minutes later, O'Neal (now with nine blocks in the past three games) turned aside a Tracy McGrady layup.
All of which left Rivers shaking his head at what O'Neal is able to do at his age. But O'Neal didn't seem overly impressed with himself.
"I'm in excellent shape," O'Neal said. "I'm only playing 19 to 20 minutes per game, so I could do that with my eyes closed. So there's really no excuse for me to be tired. I'm not really tired. Doc does a great job of managing my minutes, but we were down [eight] and I just felt like I had to do something -- dive on the floor, knock people around, get the crowd involved, and I think I helped a little bit."
A little bit? His fourth-quarter offensive outburst threatened to blow the lid off the Garden after the faithful had little to cheer about as the Celtics shot a meager 39.3 percent (22-of-56) over the first three quarters. Shaq keyed a fourth-quarter effort in which Boston shot 60 percent (12-of-20) and scored nearly a third of its total points (28) over the final 12 minutes.
Even more than his own contributions, O'Neal took time at the start of the fourth frame to give rookie Semih Erden a little pep talk, telling him to crank up his intensity (or, as Shaq phrased it, "I had to get on his [butt] a little bit.")
Erden responded with consecutive dunks, sandwiching a block in between, to give Boston its initial spark. Said O'Neal: "He understands, [and once] I got on his [butt] he came in and got a couple dunks, got a couple rebounds."
Then O'Neal did the same. But let's put his fourth-quarter exploits in proper perspective.
According to ESPN Stats & Information, O'Neal entered the game with a mere 36 fourth-quarter points in 77 minutes this season. Less than a week after scoring nine fourth-quarter points in 11 minutes against Charlotte, Shaq scored seven more in seven minutes Wednesday.
For the season, O'Neal is averaging only 3.5 second-half points over nine minutes per game. He scored eight second-half points in 12 minutes Wednesday. Over the past three games, O'Neal is averaging 8.7 second-half points over 15.3 minutes per game.
About the only thing he could lament was his inability to make Detroit pay when it went with Hack-a-Shaq, fouling him with the Pistons up two with three minutes to play.
O'Neal clanged both freebies but promised that wouldn't happen when the games matter.
"I'm kind of [ticked] at myself that I didn't hit them," O'Neal said. "I was ready to shoot them but they just didn't go in. I think if we were to have lost the game, I would've been really upset. Keep in mind, when we really, really, really need them, I'll be there and you won't have to worry about it. Studies show."
Studies also show that 38-year-old basketball players shouldn't be key contributors in the NBA, let alone on teams overflowing with younger Hall of Fame-bound talent. Instead, O'Neal is finding ways to keep both opposing centers and Father Time at bay.
And neither Rivers nor anyone else can quite explain it at times.
Chris Forsberg is the Celtics reporter for ESPNBoston.com. Follow him on Twitter.