The Boston Celtics picked a good time to play their best half of basketball this season.
The Celtics trailed the Nuggets by double digits late in the third quarter Sunday, as Denver appeared to be rolling toward its ninth consecutive victory.
Then Boston flipped the switch.
The C's closed the game out on an incredible 40-8 run, outscoring the Nuggets 31-8 in the fourth quarter to stun the NBA's hottest team in a 105-87 win.
While Jamal Murray was sidelined for Denver, this was still a remarkable victory for Boston, which has won five of its last six to move to 28-26 on the season.
Here are three observations from a wild one in Denver:
The Celtics' mental toughness finally shines through
The Celtics apparently learned their lesson from Friday night, when they collapsed down the stretch to allow the Minnesota Timberwolves to force overtime.
Jaylen Brown (12 points in third quarter) and Jayson Tatum (14 points in the fourth quarter) led an incredible second-half effort for Brad Stevens' club, which didn't let up over the final 15 minutes to step on the Nuggets' throats.
You could argue there was a bit of a role reversal in Denver, as the Celtics played with a ton of energy down the stretch while the Nuggets appeared to throw in the towel midway through the fourth.
That's a great sign for Boston, which has struggled in close games this season but now has outscored its opponent in nine consecutive fourth quarters.
This version of Jayson Tatum is scary
The Nuggets held Tatum scoreless in the first quarter Sunday, but he wouldn't be held down for long.
The 23-year-old poured in 14 points over the final 12 minutes and played a huge role in the Celtics' comeback to finish with a game-high 28 points and 10 rebounds, one game after racking up a career-high 53 points and 10 boards against the Timberwolves.
Tatum appeared to score at will in the fourth quarter, seizing the role of Boston's "closer" and even showing a little emotion as he hit a series of big buckets.
Tatum has taken criticism at times this season, but the All-Star forward has delivered in the clutch on multiple occasions and is averaging nearly 7.0 points in the fourth quarter, tied for seventh in the NBA.
Every good team needs a go-to closer late in games, and Tatum has had his moments this season. But if he can play at this consistently high level down the stretch, that will go a long way toward the C's rising in the Eastern Conference standings.
Nikola Jokic is one-of-a-kind
Name another 6-foot-11, 284-pound big man who can do this:
Jokic is the engine that makes the Nuggets run, and his unique playmaking ability helped Denver stay in front early without Murray.
The Serbian big man disappeared in the fourth quarter, though, going scoreless as Boston mounted its huge run and coming out of the game for good with 4:41 still remaining.
Jokic finished with a triple-double (17 points, 10 rebounds, 11 assists) and dazzled while he was in the game, but the Nuggets were minus-23 when he was on the bench.
The Celtics' West Coast trip continues Tuesday night in Portland against the Trail Blazers. Tip-off is set for 10 p.m. ET, with coverage beginning at 9:30 p.m. ET on NBC Sports Boston.