NEW ORLEANS -- Jalen Williams highlighted a 24-point performance with a back-breaking 3 with three minutes left, and the Oklahoma City Thunder beat the New Orleans Pelicans 97-89 on Monday night to complete a four-game sweep of their first-round playoff series.

Shai Gilgeous-Alexander had 24 points and 10 rebounds for Oklahoma City, which trailed by five in the fourth quarter before suddenly seizing control with a combination of stifling defense and opportunistic shooting.

New Orleans led 80-75 and had a chance to take what would have been the biggest lead for either team when Jose Alvarado blocked Gilgeous-Alexander and sent CJ McCollum the other way on a two-on-one break.

McCollum could not convert at the rim, however. Soon after, Chet Holmgren's putback and Josh Giddey's 3 tied it at 80 and ignited a decisive 18-2 run, capped by Williams' second-chance 3, that put the Thunder up 93-82 with 3:08 left.

New Orleans, which played the entire series without star power forward Zion Williamson, never recovered.

Giddey and Holmgren each scored 14 points. Holmgren also had nine rebounds.

McCollum scored 20 for New Orleans, which continued to be plagued by poor 3-point shooting. The Pelicans hit just eight of 34 shots from deep (23.5%).

Jonas Valanciunas had 19 point and 13 rebounds but might have produced more had he not been limited by foul trouble to 26 minutes on the court. Naji Marshall hit half of the Pelicans' 3s and finished with 16 points.

The Thunder held a 44-43 halftime lead in a game was highly competitive through three quarters, with 18 lead changes and neither team leading by more than five.

New Orleans stayed close despite Brandon Ingram missing nine of his first 10 shots and 12 of 14 for the game.

Ingram's free throws with 3 seconds left in the third quarter that gave the Pelicans a 71-70 lead at the end of the period, but he finished with just eight points when more was needed of him with Williamson out of the lineup.