If one believes in trends, it seems likely that the Phoenix Suns will win Sunday’s do-or-die Game 7 against the Dallas Mavericks in their Western Conference semifinal series.

After all, the home team has won every game of this playoff series.

But it wasn’t supposed to come to this for Phoenix. Not for the team that had the best regular-season record in the N.B.A. by far, and especially not after the Suns dominated their first two games against a Dallas team with limited playmaking outside of its star, Luka Doncic.

On Thursday night, the Suns had a chance to send the Mavericks home for the summer, only to lay an egg. Dallas got hot from 3-point range, shooting 16 for 39 (41 percent), while Doncic bullied his way to the rim for easy dunks. Doncic also repeatedly backed down and overpowered the smaller Suns point guard Chris Paul in a matchup Dallas had been eager to exploit the entire series. Doncic ended the game with 33 points, 11 rebounds, 8 assists and 4 steals.

“I don’t have enough time to talk about everything that’s eating at me,” Suns Coach Monty Williams told reporters after the game. “I didn’t think we understood the desperation they were going to play with.”

This has not been a typical seven-game series. It hasn’t been a slugfest with stars from both teams exchanging clutch baskets. None of the contests have been particularly competitive or come down to the final minutes. The only constants have been chippiness and trash talk.

But there are precedents for a playoff series like this. In 2008, the No. 1-seeded Boston Celtics faced the No. 8-seeded Atlanta Hawks in the first round. Boston won the first two games at home in blowouts, but Atlanta repeatedly and unexpectedly held serve at home. The Celtics won Game 7 by 34 points. A similar trajectory shaped Boston’s next series, against the LeBron James-led Cleveland Cavaliers, but those games were more competitive. Boston would go on to win the N.B.A. championship.

But precedent is no guarantee, and the Suns could certainly be on their way to an embarrassing second-round exit after last year’s run to the N.B.A. finals. Last year, the Bucks and Nets traded home wins for six games in the second round, then the Bucks won the finale on the road. One more off game from Paul, or a hot game from a Mavericks role player, and the Suns could be shown the door.

If the Mavericks win, they will have dethroned a Suns team that won a franchise-record 64 games, including an 18-game win streak. That kind of success is rare and difficult to repeat. For one thing, Paul, a 12-time All-Star, is 37 years old. He is still elite as a point guard and led the league in assists per game. But the list of players who excelled at age 38 is small, populated by generational players like Karl Malone, John Stockton, Michael Jordan and Kareem Abdul-Jabbar.

Paul is a generational player, too, but this has not been a particularly strong postseason series for him, particularly after Games 1 and 2. Since then, he’s been dogged by foul trouble, had difficulty defending Doncic, and has only dished out six assists a game for the series after averaging 10.8 per game during the regular season.

Not having a championship is a prominent hole in Paul’s illustrious résumé. He is 3-4 in Game 7s, not including the 2018 Western Conference finals against the Golden State Warriors, when he missed the final game because of injury as a member of the Houston Rockets.

The Suns would also be at a crossroad with the 23-year-old Deandre Ayton, who is one of the best centers in the league and set to enter restricted free agency. Phoenix did not offer him a maximum contract offer before the season, and an early playoff exit could hurt his chances of getting one now.

But the Suns have the edge entering Sunday’s game in Phoenix. They had the N.B.A.’s best home record at 32-9. They’re tested, having made the finals last year and with the experienced Paul at the reins. They’ve shown that they can withstand Doncic, who in his third playoff run and has torched the Suns, averaging 32.2 points, 9.8 rebounds and 7.5 assists through six games. Doncic has faced elimination three times in his short playoff career — including on Thursday — and he’s come up big each time, though in defeat. In a first-round Game 7 came against the Los Angeles Clippers last year, he scored 46 points in the loss. In 2020, he had 38 points in a Game 6 loss to the Clippers.

The Suns have won three games despite not being able to guard Doncic.

But what they may not be able to withstand are their own turnovers, which have bedeviled the Suns on the road. In Game 3, Paul and Devin Booker combined for 12 of them, more than the Mavericks. In Game 4, Booker had five. Paul had two, but played only 23 minutes because of foul trouble. During Thursday’s Game 6, Booker had eight, Paul had five and the Mavericks combined for just six.

The Mavericks’ strategy to beat Phoenix has been relatively simple: Match up Doncic against Paul, or spread the floor and have Doncic or his backcourt partner, Jalen Brunson, drive and find shooters. It has mostly worked. Role players like Maxi Kleber have often come through by hitting 3s.

One adjustment the Suns can counter with is stacking the paint with defenders to encourage Doncic to shoot 3s. He’s a below-average 3-point shooter, at just 29.6 percent for the series. And if he gets to the paint, the Suns need to close out on shooters to disrupt their rhythms. In Game 5, Phoenix’s best defensive performance of the series, Dallas shot 8 for 32 from 3-point range, a dismal 25 percent.

Outside of Game 5, the Suns have been consistently bad on defense and only occasionally have they been able to overcome that with strong offense. It has often looked as if the Suns were rushing their offense — unusual for a Paul-led machine.

Best thing about all these playoff games is you don’t carry a 20-point lead into the next game,” Paul said Thursday. “You know what I mean? Each game has a personality of its own and now it’s down to one game