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DENVER — Damian Jones might be starting at center for the back-to-back NBA champions, but he is still a 23-year-old just getting accustomed to all that comes with this level: the daunting individual matchups, the questionable foul calls and, perhaps most important, the heightened scrutiny.

After watching Jones’ dunk attempt get blocked by Juan Hernangomez in the final seconds of the Warriors’ 100-98 loss Sunday night to the Nuggets at Pepsi Center, many wondered why Stephen Curry would feed someone who is essentially a rookie — the vast majority of his first two NBA seasons were spent in the G League — at such a critical moment.

The answer was simple: Jones was open. And after nearly a month gaining his teammates’ trust in the starting lineup, he warranted the chance to send the game into overtime. The only problem was that, like every other player in the league, Jones doesn’t have eyes in the back of his head.

With his team down two and 2.4 seconds left, Jones caught a pass from Curry under the basket and went up hard for the dunk, only for Hernangomez to come from behind and swat the ball out of his hands.

“Steph hit me, and I went up quick,” Jones said, “but I still got blocked.”

Added Curry: “DJ still obviously has a lot to learn, and that’s great for us in terms of getting him to his full potential. But nights like tonight are where he really grows. He gains confidence with experience. I thought he played amazing.”

In the span of five nights, Jones didn’t looked overwhelmed against three of the NBA’s best big men: Oklahoma City’s Steven Adams, Utah’s Rudy Gobert and Denver’s Nikola Jokic. The big issue Sunday was that Jones picked up five fouls — at least a couple of which were questionable — that forced him to sit for key stretches.

Apparently worried about drawing more fouls, Jones got more tentative defensively as the game progressed. A night after Jokic delivered a 35-point, 12-rebound, 11-assist, four-steal gem in the Nuggets’ rout of Phoenix, the Serbian center posted 23 points, 11 rebounds and six assists.

Jones was far from Golden State’s only player who got in foul trouble. Seemingly still vexed by the league’s new freedom-of-movement rules, with referees closely monitoring contact away from the ball, the Warriors committed 29 fouls, which afforded Denver 42 free-throw tries. That the Nuggets missed 18 of them was the only reason Golden State had a chance late.

“Obviously with the freedom-of-movement stuff, we have to be a little bit more cautious before the play,” Kevin Durant said. “We have to do our work early before the play starts. Sometimes, we’re a little bit too physical. We’ve got to tone that down a bit, but still play aggressive.”

Less than a week into the season, Golden State has a lot more to work on than staying out of foul trouble.

With Andre Iguodala back from a calf issue that sidelined him for Friday’s win over the Jazz, the Warriors had nearly as many turnovers (18) as assists (22). Instead of making the extra pass to find the open man, they repeatedly chucked up contested three-pointers, going 7-for-29 from long range.

The worst culprit was Klay Thompson. Days removed from a sensational preseason, he went 1-for-6 from three-point range to put him at 2-for-16 from deep through three games.

After missing much of the preseason with a knee issue, Draymond Green is still trying to return to his do-everything ways. In 33 minutes, he had four points on 1-for-4 shooting, five rebounds and four assists.

“I don’t like the looks we’ve been getting,” Golden State head coach Steve Kerr said. “We haven’t been executing. ... We are standing too much.”

With Curry (30 points, six assists) leading the way, the Warriors rallied back from a 13-point deficit in the fourth quarter to have a chance to tie in the closing seconds. Curry drove the length of the court, saw Paul Millsap block his path to the rim and hit Jones, who to that point had hit all four of his field-goal attempts.

Roughly 20 minutes after the final buzzer sounded, Curry sat in front of his locker, thumbing through his iPhone to find video of that last play. There was nothing he saw that made him regret his decision.

Durant agreed. “I thought Damian played great,” he said. “I mean, what else could he do in that moment but go up? … You can’t ask for anything better.”

Connor Letourneau is a San Francisco Chronicle staff writer. Email: cletourneau@sfchronicle.com Twitter: @Con_Chron