The fallen champions are already in rebuild mould after the break-up of their three-time NBA-winning squad and had lost two of their first three games ahead of their match-up with Phoenix.
And their 121-110 home loss – fuelled by Devin Booker's 31 points – paled into insignificance when Curry's injury was announced.
James Harden loaded up 59 points as the Houston Rockets edged the Washington Wizards 159-158 in a classic, Bradley Beal (46 points) coming down on the losing team.
The Philadelphia 76ers saw off the Minnesota Timberwolves 117-95, Joel Embiid scoring 19 points as he got the better of Karl-Anthony Towns in their rivalry, thought tensions did spill over on the court as the pair clashed in the third quarter.
The fancied LA Clippers rested Kawhi Leonard and lost 110-96 to the Utah Jazz on the back of 29 points from Mike Conley, while Kevin Love led Cleveland to a 117-111 win over Chicago.
The Boston Celtics were impressive in a 116-105 win over the Milwaukee Bucks, Kemba Walker leading the way with 32, while Brooklyn's early struggles continue after a 118-108 loss to Indiana.
Pascal Siakam posted 30 points as reigning champions the Toronto Raptors won 125-113 against the Detroit Pistons, Damian Lillard led the Portland Trail Blazers to a 102-99 win over Oklahoma City, the Charlotte Hornets beat the Sacramento Kings 118-111 and the Orlando Magic saw off the New York Knicks 95-83.