(Photo credit: Mark J. Rebilas-Imagn Images)

Kahleah Copper scored 28 points on her 31st birthday, MVP candidate Alyssa Thomas became the first player in league history with 300 assists in three seasons, and the host Phoenix Mercury held off the slumping Chicago Sky 83-79 on Thursday.

Natasha Mack had 10 points and 12 rebounds, her first career double-double, and added a career-high five blocked shots while Thomas had 15 points and nine rebounds for the Mercury, who swept the four-game season series.

Angel Reese had 15 points and 20 rebounds, Kia Nurse had 17 points and a season-high five 3-pointers, and Kamilla Cardoso had 15 points for the Sky, who have lost eight of nine and 16 of 18 since beating league-leading Minnesota on July 2.

Copper's 3-pointer gave the Mercury a 78-73 lead with 2:28 remaining, and Thomas' free throw made it 79-75 with 1:25 left.

Cardoso's layup made it 79-77 with 1:15 remaining, but Mack blocked Reese's 8-footer on the Sky's next possession and Thomas made a short jumper for an 81-77 lead with 13.8 seconds remaining.

Reese made a layup but missed a free throw with 10.9 seconds left, and Thomas fed the rebound to Satou Sabally, who made two free throws.

Reese had her league-high 21st double-double, one more than Thomas.

The Mercury (24-14) remained one-half game ahead of the New York Liberty (24-15) for fourth place and home-court advantage in the first round of the playoffs.

The teams meet in Phoenix on Saturday, one of the Mercury's two remaining games against a team with a winning record.

Chicago had a 38-34 rebounding edge and made 10 of 20 3-pointers but committed 21 turnovers to the Mercury's nine.

The Mercury had a season-high 17 steals, five by DeWanna Bonner, and a season-high 11 blocked shots.

Thomas set up Copper for the Mercury's first basket on her 300th assist 90 seconds into the game. Thomas had 316 assists in 2023 and 317 in 2024, both with Connecticut. She was also the first with two straight 300-assist seasons.

Thomas, who has a league-high seven triple-doubles, added six assists. She has six triple-doubles in her last 11 games.

--Field Level Media