Penny Taylor tallied a game-high 28 points as 81.
Candice Dupree added 20 points and 10 rebounds for the Mercury, who have won four of five to remain firmly entrenched in second place in the West.
DeWanna Bonner posted 13 points off the bench with a game-best 11 boards for Phoenix.
Becky Hammon registered 22 points and dished out 10 assists for the Silver Stars, who have lost three in a row. Ruth Riley poured in 16 and Scholanda Robinson had 15 points in a losing cause.
The home team trailed 41-38 at the break, but used a 14-2 run late in the third quarter to forge ahead.
Taylor began the run in earnest with a three-point play to cut the Mercury deficit to 52-49, then Alexis Gray-Lawson drained a trey to tie the game
Dupree closed out the burst with two straight buckets and Phoenix led 59-54.
The lead swelled to as much as nine early in the fourth, but Riley hit from long distance to forge a 65-65 deadlock. But Taylor hit two from the line and Gray-Lawson again connected from beyond the arc to give the Mercury some breathing room.