Jewell Loyd and Breanna Stewart combined for 38 points to lead the Seattle Storm past the Atlanta Dream while Arike Ogunbowale was at the forefront of the Dallas Wings' victory over the Phoenix Mercury.
The win saw the Storm (9-2), the leaders of the Western Conference, claim the best record in the league, one-half game better than the East-leading Connecticut Sun (8-2).
For Dallas it continued a productive road trip on which they are now 3-1 heading into Sunday's meeting with the Las Vegas Aces.
Atlanta Dream 75-86 Seattle Storm
Loyd scored 20 points alongside Stewart's 18 points and 13 rebounds as the Storm notch an 86-75 victory over the host Dream to complete a two-game sweep following Wednesday's 95-71 triumph.
Epiphanny Prince scored 11 points for Seattle, who shot 50.8 per cent from the field and made 10 of 21 from three-point range compared to the Dream's 36.1 per cent and four-for-18 return from behind the arc.
Courtney Williams recorded 19 points and 11 rebounds but could not prevent Atlanta (4-6) from losing its fourth straight game, the Dream losing the two games to Seattle by an average of 17.5 points.
Cheyenne Parker added 17 points for the Dream, while Tiffany Hayes scored just 11 points on three-of-12 shooting after topping 20 in five of her previous six games.
Seattle held a 55-43 lead after a three-point play by Mercedes Russell with 6:21 left in the third quarter, but Atlanta whittled away and pulled within 60-54 on Parker's three-pointer with 1:56 remaining.
The Storm finished the quarter by scoring nine of the final 13 points, with Prince draining a three-pointer with 28.6 seconds left to make it 69-58 entering the final stanza. From there they held off five straight points from Williams with a 7-1 run, before a 6-0 push courtesy of Loyd and Stewart helped see out the win.
Phoenix Mercury 59-77 Dallas Wings
Arike Ogunbowale scored 20 points and Satou Sabally had 17 as the Wings beat the Mercury for the second time in four days, running out 77-59 winners.
Moriah Jefferson added 11 points as the Wings (5-5) won for the fourth time in their past five games, Dallas taking the season series from the Mercury 2-1 and improving to 3-1 on a five-game road trip that concludes Sunday in Las Vegas.
Brittney Griner scored 19 points, Skylar Diggins-Smith added 11 and Kia Nurse had 10 to lead the Mercury (5-5), who never led in the game.
Neither team shot well on three-point attempts as Dallas made six of 22 and Phoenix sank three of 20, but the Wings enjoyed a 40-29 rebounding advantage, their fifth straight game with at least 40 rebounds.
Jefferson and Ogunbowale each made a three-pointer during an 8-0 start to the third quarter that gave Dallas a 48-33 lead, before Kia Vaughn's layup provided Phoenix's first points of the quarter, and Griner followed with another layup.
The Wings built the lead to 16 points until the Mercury closed with a 9-2 run to pull within 57-48 at the end of the period.
Ogunbowale started the fourth-quarter scoring with a three-pointer, and she made another that put Dallas in command with a 71-55 lead midway through the period.