The Oklahoma City Thunder, fueled by 38 points from Shai Gilgeous-Alexander, held off the Memphis Grizzlies 117-115 on Saturday to complete a 4-0 sweep in their NBA Western Conference playoff series and become the first team to reach the second round.

The Cleveland Cavaliers were on the brink of advancing, taking a 3-0 stranglehold on their Eastern Conference series with a 124-87 blowout of the Miami Heat.

And the Denver Nuggets leveled their Western Conference series with a stunning 101-99 victory over the Los Angeles Clippers sealed by Aaron Gordon's put-back dunk at the final buzzer.

Jalen Williams added 23 points for the Thunder, who were pushed to the wire in Memphis despite the absence of Grizzlies star Ja Morant, who was ruled out with a hip contusion suffered in game three.

Scotty Pippen Jr. scored 30 points and Santi Aldama and Desmond Bane had 23 points each for the Grizzlies, who trailed by 12 with 3:37 to play but closed within two in the waning seconds only to come up short.

After the first three games featured a total of four lead changes, the teams traded the lead 15 times in the first three quarters.

Oklahoma City took the first double-digit lead of the game with less than six minutes remaining and, without Morant, Memphis just didn't have enough to extend the best-of-seven series.

Gilgeous-Alexander had struggled offensively by his standards in the first three games of the series.

But he looked like the player who won the regular-season scoring title as he connected on 13 of 24 shots from the field, setting an early tone with 16 points in the first quarter.

"I didn't think he played any different," Thunder coach Mark Daigneault said. "I just think he got into a groove."

The Thunder, who led the league with 68 regular-season wins, next face either the Denver Nuggets or Los Angeles Clippers, who were tied at 2-2 after the Nuggets' sensational victory in Los Angeles.

Three-time NBA Most Valuable Player Nikola Jokic scored 36 points with 21 rebounds and eight assists for the Nuggets, who led by 22 early in the fourth quarter.

The Clippers, led by 24 points from Kawhi Leonard and 22 from Norman Powell, surged back to take their first lead of the game, 97-96, on Bogdan Bogdanovic's reverse layup with 1:11 to play.

Jokic spun through traffic for a basket that put Denver back on top, but Ivica Zubac tipped in a basket to tie it at 99-99.

With little more than a second remaining Jokic unleashed a high-arching three-point attempt that missed, Gordon nabbing the rebound and thrusting the ball in the hoop for a game winner that required an agonizingly lengthy video review before officials confirmed he had, indeed, beaten the buzzer.

"That's a crazy game, man, crazy game," Gordon said.

Cavs pummel Heat

In Miami, the Cavs handed the Heat the worst playoff defeat in franchise history, despite the absence of All-Star guard Darius Garland and a relatively quiet 13-point game from Donovan Mitchell.

Jarrett Allen scored 22 points and De'Andre Hunter added 21 off the bench as six Cavs players scored in double figures.

The Heat, well aware that no NBA team has rallied from 3-0 down to win a playoff series, got off to a fast start and led by nine midway through the first quarter.

But the Cavs were up by 13 by the end of the first quarter, their lead never dipping below double digits the rest of the way.

"We took the first punch and from there we just took the game over," said newly minted Defensive Player of the Year Evan Mobley, who chipped in 19 points.

Bam Adebayo scored 22 points to lead the Heat, but the 37-point margin of defeat surpassed the Heats previous worst post-season loss, a 36-point defeat to the San Antonio Spurs in game three of the 2013 NBA Finals — when the Heat went on to win the title.

In San Francisco, Stephen Curry shook off a slow start to score 36 points with seven rebounds and nine assists as Golden State pulled away late for a 104-93 victory over the Houston Rockets that put the Warriors up 2-1 in their series.

The Rockets had a one-point lead with less than six minutes remaining in the bruising back-and-forth battle that featured 18 lead changes.

Gary Payton II then scored four straight baskets for the Warriors and fed Curry for a three-pointer that gave the Warriors a 95-86 lead.

The hard-fought victory came without star forward Jimmy Butler, who suffered a pelvic contusion in a hard fall in game two.