PHOENIX (AP) -- Tameka Johnson made a big difference for the Seattle Storm on Friday night.
Johnson had 23 points and three assists to lead the Storm past the Phoenix Mercury 81-73.
"I was just taking what they gave me," said Johnson, who scored on four layups, three jumpers and was 8-for-8 from the free throw line.
"With a team like Phoenix and all the talent and threats they have, you can't be lax against them. You have to keep them on their toes."
Tina Thompson added 18 points and seven rebounds for Seattle (13-13), which has won all four meetings with Phoenix (14-13) this season and has won four of the past five overall.
"It's hard to measure on statistics," Seattle coach Brian Agler said. "Some of our stats aren't real impressive but for whatever reason, they really play well together. We've gotten better throughout the year. They are sort of a team of intangibles."
Candice Dupree had 17 points while Diana Taurasi added 16 points and seven assists for the Mercury, who lost for just the second time in six games under interim head coach Russ Pennell.
"The thing that bothers me is that it's the little things right now that's keeping this Phoenix Mercury team from being great," Pennell said.
"(We're) very talented, have a lot of positives, but it's the little things that are killing us right now. We're not boxing out, we're turning the ball over at an alarming rate."
No. 1 draft pick Brittney Griner had 12 points and five rebounds for the Mercury.
Pennell also had some advice for his rookie.
"She's going to have to start doing some things we ask and she's going to have to start paying attention to detail and I think she will," Pennell said. "She wants to do it. ... I'm not calling out Brittney here in front of the press, but frankly, she does need to improve and this is not anything I haven't told her."
With the win, the Storm moved within a half-game of Phoenix for third in the Western Conference with eight games to play.
"Our team is doing many things now that a lot of people did not think we could do before the season started," Agler said. "I would probably have to put myself in that category."
The Storm had a double-digit lead throughout the final period after taking a 63-53 advantage going into the fourth until the final two minutes.
Camille Little added 17 points and five rebounds for Seattle, which took advantage of 15 Phoenix turnovers, scoring 19 points off the mistakes.
"I think that in every occasion we try to play in our space," Thompson said. "You guys are here every game and you know how amazing Diana is.
"Literally, she is like the head of the snake. We do everything that we can to not let her get as comfortable as possible, because once Diana gets it going, it is really tough to stop her or cool her off."
DeWanna Bonner had 20 points, five rebounds and four assists for the Mercury.
Johnson scored 16 first-half points to help Seattle take a 44-34 lead at the break.
"Tonight we were poised and we took what they gave us," Johnson said. "You can't ever fall asleep on anybody in this league."
Sparked by back-to-back baskets by Thompson, the Storm went on a 12-1 run to open the second quarter and grab a 33-22 advantage.
"They made it hard for us to do anything on the offensive end," Taurasi said. "Defensively I thought we did good in the second half -- we limited them to some tough shots."
Johnson did her work in just 23 minutes, going out briefly with 2:47 left in the third after getting hit in the face on a play. She did not play in the fourth.
Johnson and Agler said after the game that Johnson passed neurological tests for a concussion, but that she was kept out in the fourth as a precaution.
Phoenix had started the game by making eight of its first nine shots, but committed five turnovers in the opening period, leaving the game tied at 21 after 10 minutes.
It was Seattle's first season sweep of Phoenix since 2010.
