MEMPHIS, Tenn. (AP) — Kawhi Leonard scored 21 points and San Antonio routed Memphis to sweep the best-of-seven series and advance to the Western Conference semifinals.

The Spurs finished off their ninth sweep of a postseason series in franchise history, their third against the Grizzlies. San Antonio also swept Memphis in the 2004 first round and the 2013 Western Conference finals.

The only thing that delayed the Spurs advancing was a power surge that knocked out the lights, stopping the game for about 20 minutes in the second quarter.

San Antonio now awaits the winner of Oklahoma City-Dallas, a best-of-seven series that the Thunder lead 3-1.

LaMarcus Aldridge scored 15 points and grabbed 10 rebounds for the Spurs. Tony Parker added 16 points. David West had 11.

CELTICS 104, HAWKS 95, OT

BOSTON (AP) — Isaiah Thomas scored 28 points, hitting a corner 3-pointer with 30 seconds left in overtime and then adding a pair of clinching free throws as Boston sent its first-round playoff series back to Atlanta tied two games apiece.

Paul Millsap scored 45 for the Hawks — a career playoff high and one off his all-time best — and added 13 rebounds.

Marcus Smart scored 20 points — including 11 straight for Boston in the fourth quarter — and Jonas Jerebko had 16 points and 10 rebounds.

Game 5 is Tuesday night in Atlanta.