Dream coach Michael Cooper may have been ready to flip out but then Shoni Schimmel flipped a switch against the Phoenix Mercury on Wednesday, and the rookie guard scored 20 of her career-high 24 points in the second quarter and Atlanta ripped the WNBA’s top team 96-82 at Philips Arena.

Atlanta carried a five-game losing streak into the game, and had lost nine of 11, yet handed Phoenix just its second loss in 23 games to clinch the No. 1 playoff spot in the East for the first time in the franchise’s seven-year history.

Schimmel had plenty of help as one of the WNBA’s coldest teams lit up the very hottest with a 37-15 second period that gave Atlanta a 55-41 halftime lead — even without two-time WNBA scoring champion Angel McCoughtry (tendinitis in feet).

Guard Tiffany Hayes added 19 points for Atlanta, and Aneika Henry, starting in place of McCoughtry, pitched in career highs of 15 points and 12 rebounds to help Atlanta build a 45-28 rebounding edge.

Schimmel had not scored more than 17 for Atlanta although she scored 29 three weeks ago to land MVP honors in the WNBA All-Star game.

“[Before the game, Cooper] said, ‘What are you going to bring to this team?’ He asked every single one of us,” Schimmel said after shooting 6-for-9 in the second quarter, including 2-for-4 3-pointers and 6-for-7 free throws.

“We just fed off each other’s energy. That was something we talked about at the beginning, just go out there and feed off of each other; we’re in this together.”

Sure, Mercury star Diana Taurasi missed her first game of the season, resting one night after Phoenix clinched the No. 1 playoff spot in the West, and starting guard Penny Taylor had the night off as well.

Yet Phoenix looked its usual part in scoring the final six points of the first period to take a 26-18 lead.

Then, Schimmel and Henry happened, and the Mercury stopped nearly everything they were doing. Atlanta outscored Phoenix 62-28 over the second and third quarters.

“We were just getting our butts kicked, basically, in all the effort areas,” Phoenix coach Sandy Brondello said.

“I don’t care whether Diana Taurasi or Penny Taylor was in or out,” Cooper said. “It was Phoenix and they’re the best team in the league. This was a big win for us because now we’ve beaten every team in this league.

“We needed the win, probably more so than them … to stop the bleeding. Now we can work on getting our game together going into the playoffs.”

Phoenix was led by Erin Phillips’ 21 points. Starting center Brittney Griner (nine points, five rebounds, three blocks) was pulled for good with 3:58 left in the third quarter and Atlanta leading 70-50.