It’s an age-old basketball cliché for a reason:

Defense wins championships.

The Connecticut Sun have had the best defense in the WNBA this season, and it showed Sunday when they thwarted a top-three offense — Caitlin Clark and the Indiana Fever — in their playoff opener. Once the Sun found their offensive rhythm, this game was a blowout.

The Sun won 93-69 to take a 1-0 series lead in the best-of-three. Connecticut can close out the series and keep Indiana from playing another home game with a win on Wednesday.

Caitlin Clark, welcome to playoff basketball — she had a bruise under her eye after being poked there in the first quarter, but added that wasn’t the reason her shooting sucked. And it sucked. Clark started 0-of-8 from 3, didn’t hit her first shot from beyond the arc until midway through the third quarter, and she finished with 11 points on 4-of-17 shooting, including 2-of-13 from 3.

“I had some really good chances. I felt like I had three pretty open 3s in the first half, like you usually do,” Clark said after the game. “So that’s tough, but I felt like I fought and did my best.”

Give the Sun’s DeWanna Bonner and teammates credit for taking away Clark’s flow — and it wasn’t just Clark. The entire Fever squad struggled to find a rhythm against the Sun, shooting 6 of 28 (21.4%) from 3 for the game.

Taking a team out of their flow and making the game a little ugly is what good defenses do. That’s what Connecticut did on Sunday.

Two other things went down for the Suns. One was their All-NBA two-way force Alyssa Thomas recording her fourth career triple-double with 12 points, 10 rebounds and 13 assists.

The other thing that changed the game was when Tyasha Harris had to leave the game in the first quarter after twisting her ankle on a closeout. That put pressure on backup Marina Maybrey to step up — and she did, scoring 27, the most points ever off the bench in a WNBA playoff game.

The game was close early on. The Sun led 23-20 after the first quarter, thanks in large part to the six offensive rebounds they grabbed, which gave them plenty of second-chance points. Well, that and Bonner, who scored 10 in the first quarter, including a pair of 3s.

The game began to turn when the Sun went on a 9-0 run late in the first half and extended their lead to eight at halftime, 46-38. Connecticut turned the tide against the Fever by taking advantage of every opportunity they got, which not only led to points but also to fouls.

Clark finally began to find a rhythm in the third period, but so did Connecticut’s Mabrey — a midseason trade acquisition from Chicago — who had 11 points in the quarter. The Sun extended their lead to 15 by the end of the third period. Then came the fourth period, and the Fever seemed to be what they were, the less experienced team in key moments. The Sun stepped on the gas, and this was a blowout.

Kelsey Mitchell led the Fever with 21 points, while Aliyah Boston showed off her improved skills on the short roller, finishing with 17 points and 11 rebounds.

Connecticut’s defense will be there for Game 2 on Wednesday. If the Fever can’t find a way to adjust, their season is over.

In other action from the first day of the WNBA playoffs:

New York 83, Atlanta 69: Top-seeded New York started the game 6-of-6 shooting, built a 15-point lead in the first quarter and never turned a corner against an outmatched Atlanta team in their first playoff game of the series.

Brianna Stewart had her usual monster game with 20 points and 10 rebounds, but it was rookie Leonie Fiebich who led New York with 21 points.

Atlanta’s leading scorer this season, Rhyne Howard, started the game 1-for-9 from the floor, struggled against the Liberty defense, but still finished with a team-high 14 points. New York can close out the series at home in Game 2.