PHOENIX (AP) -- With playoff position already determined, a late-season game against a last-place team can have its challenges.
The Phoenix Mercury took care of that in the first quarter Friday and, for good measure, in the fourth quarter, too.
Diana Taurasi had 20 points and 10 assists and the Mercury beat the San Antonio Silver Stars 82-61 Friday night for their fifth win in six games.
''We want to play well. I think that's the hard part here is you want to get some people some rest,'' Phoenix interim coach Russ Pennell said. ''But you don't want to pull your foot off the accelerator to the point that you are not getting good reps.''
The Mercury, No. 3 in the Western Conference, complete the regular season at Los Angeles on Sunday and then face the second-seeded Sparks in the first round of the playoffs beginning Thursday at the Staples Center.
''We wanted to get that win, show that this game meant something to us,'' said No. 1 draft pick Brittney Griner, who added 13 points and five rebounds in 21 minutes for Phoenix. ''Definitely good momentum going into play L.A.''
The Mercury (19-14) hit four straight 3-pointers to start the fourth quarter, scoring 21 straight points to open an 80-52 lead with 3:29 left.
''They hit a lot of open 3s in transition,'' San Antonio's Jia Perkins said. ''They did a good job of spreading the floor out and they hit a lot, a lot of shots and it was kind of wide open for them.''
Danielle Adams and Shenise Johnson each had 11 points for San Antonio (11-22), which has lost four straight and five of six.
San Antonio was within 59-52 going into the final quarter but missed its first nine shots of the period.
''I told the team I just wish I could have had them a little fresher,'' Silver Stars coach Dan Hughes said. ''I think we expended a lot of energy to put us down seven at the end of three and then in the fourth quarter we just didn't have the legs to finish.''
Penny Taylor had 10 points, seven rebounds and four assists in 21 minutes for Phoenix in just her third game since July 18, having missed 14 games with a knee injury.
''We're getting some momentum at the right time when we need it,'' Taylor said. ''Defensively I think we look like a really cohesive unit out there at times.''
Phoenix, in the postseason for the fourth time in five seasons, is 9-3 under interim coach Russ Pennell and finished the year 9-7 at home.
Griner had 13 points, making all six of her shots, and four rebounds in the first half to help the Mercury go up 40-31 at the break. The Mercury took advantage of San Antonio's slow start.
The Silver Stars missed seven of their first eight shots and trailed 15-2 after 5 1/2 minutes. Phoenix led 25-8 late in the first, having made 11 of its first 16 shots.
After a solid first half, Griner landed awkwardly on her right ankle after guarding San Antonio's Jayne Appel on the first basket of the second half and went out for several minutes, getting re-taped and then returning late in the third. She did not play the fourth quarter and was soaking her foot in ice water after the game but said it felt fine.
With only one practice over the last week during a stretch of five games in eight days to end the season, Pennell said his team only has games to improve.
''We have to get better. Not only do we have to win, we have to get better,'' Pennell said. ''I thought tonight we played long stretches of pretty good basketball.''