Throughout the playoffs, Jordan Loyd has been Method acting. You won’t see him on stage or screen. He’s not even an aspiring thespian; he’s a basketball player. Loyd spent the NBA season playing for Toronto’s G League affiliate, Raptors 905. Throughout the playoffs, Loyd has been playing on Toronto’s practice squad, mimicking the behaviors of different Raptors opponents. In the second round he was Ben Simmons, and during the Finals, Loyd has played Steph Curry. He knows better than anyone how ferocious this Toronto defense has been on Curry. “It’s hard for me to even catch the ball,” Loyd told me after the Raptors’ decisive 105-92 Game 4 win in Oakland on Friday. “I can’t imagine what it’s like for Steph.”

We don’t have to imagine. We saw it Friday night. It’s hell. Curry was exhausted by the fourth quarter, and appeared frustrated by the special attention the Raptors gave him, often grimacing or hanging his head. Sometimes Steph even hesitated to launch shots. The defensive pressure is similar to what he saw against the Cavaliers in the 2016 Finals and the Rockets in the 2018 Western Conference finals. Those Warriors teams always found a way. This one hasn’t, and now the Raptors are on the brink.

There have been plenty of upsets in NBA Finals history—Mavs over Heat in 2011 and the 1975 Al Attles Warriors beating the Bullets, to name just two. No Finals upset is exactly alike, but the one we’re on the verge of, with Toronto one game away from besting Golden State, shares qualities with two previous shockers: the Pistons’ defeat of Kobe and Shaq’s Lakers in five games in 2004, and the Spurs’ win over the Heat in 2014, also in five games.

In both of those cases, the underdog caught the favored team on the precipice of a roster breakup, just as Toronto is catching the Warriors at what could be the end of the Kevin Durant era. And both the Pistons and Spurs won their championships largely thanks to their defense, finishing the regular season in the top five and getting even better in the playoffs. That’s exactly what the Raptors are doing this season. They finished second in defensive rating, and then they went on to blot out stars like Joel Embiid, Ben Simmons, Giannis Antetokounmpo, and now Steph Curry. Toronto is holding the Warriors to only 106.6 points per 100 possessions when their franchise player, Curry, is on the floor in the Finals, their worst mark in a series since they blew a 3-1 lead to the Cavaliers in 2016 (106.4). That Cavs team face-guarded Steph off the ball and tugged and bumped him as he sprinted through screens, all to wear him down. But the Raptors have taken it even further with their surprising box-and-one strategy, and by applying tons of pressure from half court.

Toronto contained Steph Curry, a couple Magic Johnson–esque takes, and the Warriors’ chances of coming back from down 3-1.@KevinOConnorNBA, @JohnGonzalez, and @YourManDevine recap Game 4. #NBAFinals pic.twitter.com/nobA4PJrry — The Ringer (@ringer) June 8, 2019

Stopping Curry is no small feat. By this point, everyone knows his arsenal: The two-time MVP can pull up from the logo or score balletically in the paint. Even if he gives up the ball, he never stops moving; the relocation 3-pointer is a trademark of his game and a staple of the Warriors offense. But the Raptors have a counter for everything. Toronto has pressured Curry since the opening tip of Game 1, making it quickly apparent just how much the Warriors need Durant. Toronto was even more aggressive against Curry in Game 4, stalking him all over the floor and executing even crisper off-ball rotations and switches to contain the point guard.

If it seemed like the Raptors knew what was coming all game, it’s because they sort of did. Curry’s poor shooting—9-for-22 from the field and 2-for-9 from 3—isn’t just a cold spell, it’s the intended result of a defensive game plan: preparation by the entire coaching staff and roster, from the starters to the scout team. Raptors reserve forward Malcolm Miller told me after the game that their practices and film sessions spend extensive time on “pick-up points”—areas of the floor where they “pick up” coverage on Curry, such as when he crosses half court, or off the catch at the 3-point line. In other words, all over the place.

Head coach Nick Nurse had Loyd simulate Curry on their scout team. Loyd told me he’s spent countless hours watching film of Curry to study the minutiae of his habits, from his off-ball movements to his tendencies setting screens. It’s meant to prepare the Raptors for the real deal. “Jordan has been a true professional all year after a great season in the G League,” Kyle Lowry told me. “His help has been phenomenal.”

So here’s what all the prep looked like in the game: If Curry initiated the offense, Fred VanVleet was in his grill while a teammate lurked nearby. Late in Game 4, the Warriors went as far as having Draymond Green screen for Curry in the backcourt to give him a downhill driving lane toward a pull-up 3 or the basket. It didn’t help. When Curry would pass and do his usual shebang, zigzagging through mazes of screens, two Raptors were always there trapping him as soon as he caught it.

Toronto was as aggressive as it’s been all series in helping off Golden State’s poor non–Klay Thompson shooters to push Curry off the 3-point line and into the paint, where even more defenders would be waiting to induce him into a tough shot or into a pass to one of said poor shooters.

In the clip above, Curry gets by VanVleet, but then Kawhi Leonard is hovering nearby, with both Pascal Siakam and Marc Gasol in the paint. What are you supposed to even do in that situation? Curry made the right play by kicking the ball out to Draymond, but Green promptly clanked the ball off the side of the backboard. It can often seem like a team needs six defenders on the floor to stop Curry, but five was enough for the Raptors because they had a natural power play: It was like the Warriors were playing with three or four players anyway due their scarce shooting.

Curry is seeing ghosts against the Raptors; even if a defender wasn’t nearby, he felt their presence. How could you blame him? What Toronto did worked no matter what. They trapped pick-and-rolls with Gasol or Serge Ibaka keeping their arms high to clog passing lanes:

They pushed and shoved Curry as he ran through screens like a boxer attacking his opponent’s body to wear him down physically until it affects his mind. The physical fatigue led to mental fatigue, resulting in sloppy decisions.

VanVleet had another masterful defensive performance, picking up Curry from half court to prevent pull-up 3s and mirroring his every movement off the ball.

The series will be remembered as the time an NBA head coach actually used the box-and-one defense, a middle school scheme, to contain Curry. Toronto used it again at the end of the third quarter, when Kerr rolled out a lineup with Curry, Quinn Cook, and three nonthreats from downtown. Kerr was forced to put the only other shooter he has—Thompson—back onto the floor to counter the defense.

Kerr doesn’t have many options thanks to his depleted roster. It says it all that Andrew Bogut, who is washed; and DeMarcus Cousins, who looks way behind the pace athletically; and Kevon Looney, who is playing with a painful injury, are all better options than young bigs Jordan Bell and Damian Jones, or veteran Jonas Jerebko. It’s hard to find quality late-first-round draft picks or ring-chasing veteran free agents when so much salary is committed to four superstars, and the Warriors are paying the price now with Durant out. I know what you’re saying: Cry me a river. But problems are relative, and Golden State’s have been exploited.

Some tweaks could be in order: How have we not yet seen a Curry-Thompson backcourt with Andre Iguodala and Alfonzo McKinnie at forward, and Draymond at center? The spacing still wouldn’t be great, but Kerr hasn’t tried it yet during the playoffs. At least this lineup would maximize shooting without compromising size or defensive versatility, like lineups with Livingston instead of Iguodala or McKinnie do. Curry is the only player who can generate shots for himself and others. So the goal should be to get Curry more field goal attempts. Is 22 shots and nine 3s really enough for Curry in a must-win Game 4? The Raptors did everything right in getting the ball out of his hands. Curry often makes the choice to pass to open teammates, but aside from him and Thompson, the Warriors are shooting only 26.6 percent from 3 in the series. For as long as Durant is out, having Curry take control like he did in Game 3—47 points on 31 shots—might be the only solution to extend the series long enough for Durant to return.

It’s desperation time for the Warriors thanks to a Raptors defense that has neutralized threats every step of the way. The Raptors stomped on the Magic, shut down Ben Simmons and Joel Embiid, and made Giannis Antetokounmpo look mortal. Now it’s Curry under the pressure, as the Raptors return home for a chance to complete one of the most improbable Finals runs and one of the greatest upsets the league has ever seen. Leonard, Gasol, Nurse, Lowry, and team architect Masai Ujiri will likely receive all the plaudits. But we shouldn’t forget Loyd. Just because we didn’t get to see him doesn’t mean he didn’t contribute.