LOS ANGELES – A few days removed from his 39th birthday, flecks of grey now in his hair and beard, Tim Duncan sat on the Staples Center scorer's table late Tuesday, watching the chaotic scene unfold in front of him in the final seconds of the 239th playoff game of his storied NBA career. The game hung in the balance, the atmosphere thick with tension, and yet in that small moment Duncan looked utterly comfortable – happy, even – at what awaited him and his San Antonio Spurs.

"It's just a realization of mortality, I guess," Duncan told Yahoo Sports late Tuesday. "I know my time is winding down so I'm enjoying it more."

After all these 18 seasons, Duncan's old-school game still looked as timeless as ever for one more night. He totaled 21 points, 11 rebounds, four assists, three steals and one game-changing block, playing all but 10 minutes in a 111-107 victory over the Los Angeles Clippers that left the Spurs with a 3-2 lead in the best-of-seven series and needing one more victory to reach the second round.

Clippers coach Doc Rivers complained long and hard about the game's officiating. But when the subject of Duncan's play was raised, Rivers' tone immediately changed.

"He's a consummate pro," Rivers told Yahoo Sports. "He never gets too high or low. It's like he's the easy button they have on that old [Staples] commercial. He's their easy button. You knew tonight he was going to come and play. On nights where they don't need him, he's cool with that, too."

Duncan is making $10.3 million in the final year of his contract, which means there's a chance the Spurs could be seeing their greatest player's final days. Nights like Tuesday are a reminder that Duncan still has the ability to defy his age and play longer if he desires.

The Spurs have at least two more games left in their season thanks to Duncan. After Blake Griffin totaled 21 points, eight rebounds and three assists in the first half, Spurs coach Gregg Popovich had seen enough and decided to put Duncan on him midway through the third quarter. With Duncan largely guarding him in the final quarter, Griffin missed eight of his nine shots.

With 59.9 seconds left and the Spurs leading 107-105, Griffin tried to go over Duncan for a game-tying layup. Duncan blocked the former dunk champion's shot.

"He was coming dead at me and my choice was either to go contest the shot or give up a dunk," Duncan said.

Griffin tried to go up again for another shot, but lost the ball after it was stripped by Spurs forward Boris Diaw. Popovich said Duncan's block on Griffin "might have been the play of the game."

"He's played long enough, he's got basketball IQ and he has excellent timing so he reads things well," Popovich said.

Duncan and Popovich are pursuing a sixth NBA championship together, putting them among the great player-coach duos – a group that includes Bill Russell and the late Red Auerbach; Michael Jordan and Phil Jackson; and Magic Johnson and Pat Riley.

"The reason their franchise has been great is Pop and [Duncan]," Rivers told Yahoo Sports. "The reason is [Duncan is] a superstar and he cooperates with his coach. He allows him to be the leader and the coach of the team. And he's the second leader. And I think that is so important.

"That should be [Duncan's] legacy. Forget the basketball part. He's allowed that franchise to be great because it's never been about him."

Duncan and the Spurs know this is just the first round and their 3-2 series lead is tenuous. Rivers also is confident his team, which won Game 4 in San Antonio, will be ready to get another road victory on Thursday needed to force a deciding Game 7 in Los Angeles on Saturday.

"They are going to try to knock us on our heels and attack the basket however they can," Duncan said. "We know the aggression they are going to come with, so we just have to be ready for that."

Duncan isn't taking what could be his final games for granted. If the Clippers win the next two games, it's possible Duncan's career could come to an end on Saturday.

"I know I am blessed to be out here," he said. "I know I am blessed to still be playing and feeling as healthy as I am. So I'm enjoying the ride."

Rivers hopes to end Duncan's season, but he doesn't believe it's time for Duncan's career to end.

"He loves it too much," Rivers said. "It makes him happy. I will always say with the superstars, they should always play until they just can't play. So what that there are nights where he can't be Duncan? But he enjoys it. Why not do what brings you joy?"

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