Frenchman Wembanyama added eight rebounds, six assists, three blocks and two steals at Madison Square Garden as the Spurs cut the Knicks’ lead to 2-1 in the best-of-seven championship series.
“We’ve done what we were supposed to do but the job is absolutely not done,” the 22-year-old Wembanyama said. “We’re not even halfway. The hardest is yet to come.”
The Spurs knew no team had ever won an NBA playoff series after losing the first three games, helping push them after late-game blunders cost them in a game-two home loss.
“Less mistakes, more control,” the 7ft 4in (2.24m) Wembanyama said.
“It’s the little things. We were more serious. Less mistakes. Less turnovers.”
Stephon Castle added 23 points for the Spurs while Dylan Harper had 13 off the bench.
“He has got great poise,” Wembanyama said of Castle.
“It’s hard to put into words how valuable he is to us.”
Jalen Brunson led New York with 32 points while OG Anunoby added 28, but the Knicks shot 40-of-88 from the floor and only hit 13-of-37 from three-point range.
“What was better in the defence was communication, being early,” said Wembanyama.
The Knicks’ win streak was halted two shy of the NBA playoff-record 15 in a row won by Golden State on the way to the 2017 title.
The Spurs seek their sixth NBA title and first since 2014 while the Knicks won their only crowns in 1970 and 1973.
A raucous crowd created an electric atmosphere for the first NBA Finals game at Madison Square Garden since 1999.
That included boos for Trump, the first sitting president to attend an NBA Finals game, when he was shown on the arena videoscreen.
Expanded security measures for Trump’s attendance led to fans being asked to arrive two hours before tip-off and cancellation of a watch party outside the arena.
Game four is also in New York, on Wednesday.