That defeat pushed the Lakers toward Phil Jackson, who coached Bryant and O’Neal to three straight titles. Their bid for a fourth was cut short when Duncan and the Spurs eliminated them in the second round in 2003. The Spurs then cut down Nowitzki and the Dallas Mavericks in the Western Conference finals.

If not for Duncan, Bryant might have his coveted sixth championship ring by now, to tie Jordan. If not for Duncan, perhaps Nowitzki might have two or more.

Instead, Duncan grabbed his second title in 2003, leading the Spurs to a 4-2 finals victory over Kidd and the Nets, who have not reached such heights since. Coach Byron Scott was fired the next season. Kidd had to go to Dallas to win a title. And the Nets, with no New Jersey legacy to anchor them, and scant fan support, moved to Brooklyn in 2012.

In 2005, Duncan and the Spurs struck again, claiming their third championship while denying a repeat title to Billups and the Detroit Pistons. Within weeks, Coach Larry Brown dumped Detroit for New York, for a turmoil-filled season with the Knicks. The Pistons have not come close to the title again.

No single franchise has suffered as much at Duncan’s hands as the Phoenix Suns. From 2004 through 2008, the Suns were the darlings of the N.B.A. — a running, gunning, 3-point shooting offensive dynamo. With Nash orchestrating D’Antoni’s offense, the Suns electrified the league, averaging 58 wins over four seasons and making the conference finals twice.

But they never made the finals. Because of Duncan.

The Spurs knocked out the Suns in 2005, 2007 and 2008, putting a damper on the era and hastening the departure of D’Antoni, who left Phoenix for New York.

How far would the Suns have gone if not for Duncan?

“I think it’d have been one or two championships,” said Boris Diaw, a staple of those Suns teams and now a Spurs reserve.