Paolo Banchero has led the eighth-seeded Orlando Magic to a stunning upset win over top-seeded hosts Detroit, extending the longest home playoff losing streak in NBA history.

Banchero scored 23 points and had nine rebounds and four assists in a 112-101 victory on Sunday night in Game 1 of their Eastern Conference first-round series.

Detroit have now dropped 11 straight home games in the postseason, a drought that dates to 2008.

Detroit's Cade Cunningham scored a playoff career-high 39 points and Tobias Harris added 17 for the Pistons, but the rest of their teammates were quiet offensively.

Franz Wagner scored 11 of his 19 points in the fourth quarter to help seal the victory for the Magic, who never trailed.

The Pistons haven't advanced beyond the first round in the postseason in 18 years and the Magic haven't since 2010.

In Oklahoma City, Shai Gilgeous-Alexander scored 25 points as the host Thunder continued their NBA title defence with a 119-84 rout of the Phoenix Suns in Game 1 of their Western Conference first-round series.

The reigning MVP made just five of 18 field-goal attempts but went 15-of-17 at the foul line before sitting out the fourth quarter.

Jalen Williams scored 22 points and Chet Holmgren added 16 for the top-seeded Thunder.

Devin Booker scored 23 points and Dillon Brooks scored 18 on 6-of-22 shooting for the Suns, who shot just 34.9 per cent from the field.

In Boston, Jayson Tatum had 25 points, 11 rebounds and seven assists in his first playoff game since rupturing his right Achilles tendon last season, as the Celtics rolled past the Philadelphia 76ers 123-91 to kick off their Eastern Conference first-round series.

Jaylen Brown scored 26 points and Neemias Queta added 13 for the second-seeded Celtics. They never trailed, building a 35-point lead as coach Joe Mazzulla gave minutes to 12 players.

Tyrese Maxey had 21 points and eight assists for the 76ers, who played without Joel Embiid, still recovering after an appendectomy on April 9.

In San Antonio, towering French superstar Victor Wembanyama scored 35 points in his playoff debut as the second-seeded hosts rolled to a 111-98 victory over the Portland Trail Blazers in Game 1 of their first-round Western Conference series.

Wembanyama's 21 first-half points set an NBA record for the most in the opening half of an NBA playoff debut since the league's play-by-play era began in 1997. His 35 total points set a Spurs franchise record for the most in a playoff debut, surpassing Tim Duncan's 32 in 1998.

Stephon Castle and De'Aaron Fox each added 17 points and combined for 15 assists for San Antonio.