Jaylen Brown and Jayson Tatum combined for 69 points as the Boston Celtics won their third straight game, defeating the Washington Wizards 126-107.
Brown and Tatum scored 36 and 33 points respectively, while Porzingis added 15 in his return to Washington after an off-season trade between the two teams.
It is the second successive season the Celtics, who reached the Eastern Conference finals last time out, have begun with three straight wins.
Their efforts were eclipsed by Dejounte Murray, who matched his career-best haul with 41 points as he helped the Atlanta Hawks come from 19 points down at half-time to beat the Minnesota Timberwolves 127-113.
Steph Curry shrugged off the absence of Klay Thompson with a knee injury as he inspired the Golden State Warriors to a 130-102 win at the New Orleans Pelicans.
Curry scored 42 points, opening with a pair of three-pointers from 25 feet and wrapping his scoring up from 31 feet.
The Dallas Mavericks remain unbeaten as Luka Doncic grabbed a triple-double with 35 points, 12 rebounds and 12 assists in a 125-110 win over the Memphis Grizzlies.
Nikola Jokic also recorded a triple-double – his second of the season – with 27 points, 11 assists and 10 rebounds as the Denver Nuggets saw off the Utah Jazz 110-102.
Giannis Antetokounmpo scored 33 points for the Milwaukee Bucks as they avenged being eliminated by the Miami Heat in last year’s play-offs with a 122-114 win, despite 35 points from Tyler Herro.
Cam Thomas scored 33 points as the Brooklyn Nets beat the Charlotte Hornets 133-121 for their first win of the season, while Nikola Vucevic inspired the Chicago Bulls as they came from behind late to inflict a first defeat on the Indiana Pacers, 112-105.
The Portland Trail Blazers also claimed their first win, Jerami Grant scoring 22 points as they beat the Toronto Raptors 99-91, while 32 points from Shai Gilgeous-Alexander lifted the Oklahoma City Thunder past the Detroit Pistons.
The Los Angeles Lakers needed a late 12-5 run to come from behind and beat the Orlando Magic 106-103, leaving the Celtics as the only undefeated team in the Eastern Conference.
