Trailing 41-24 midway through the second half, the Mercury appeared on course for a heavy defeat, but the Monarchs had not counted on Pondexter.
The former Rutgers star led the way in a stunning fightback, and finished with 23 points and five assists.
The turning point actually came after Pondexter’s club and international team-mate Diana Taurasi had been ejected for a second technical foul - something which seemed to strengthen the Mercury’s resolve.
Sacramento's Rebekkah Brunson had a chance to win the game in the final moments but she missed a shot in the paint as the Phoenix defense collapsed on her.
Brunson finished with a team-high 16 points.
Another Team USA star, Tamika Catchings, was also having a big night as she collected 21 points, six rebounds and six assists to help the Indiana Fever to an 89-75 win over the Minnesota Lynx.
Tamika Whitmore added 17 points on a night when the Fever dominated from tip-off.
Catchings and Whitmore combined to shoot 15 of 29 from the field, including five of nine on three-pointers.
Minnesota’s own US international, Seimone Augustus, finished with 23 points for the Lynx.
The San Antonio Silver Stars ran riot in the second quarter as they came from behind to beat the Houston Comets 82-71.
San Antonio outscored their hosts 24-7 in the period to overturn a 10-point deficit and take control of the game.
Guard Becky Hammon scored 10 of her game-high 26 points in the decisive quarter for San Antonio.
Houston wasted 20 points and 12 rebounds from Michelle Snow and 18 points from her Team USA team-mate Tina Thompson.
Courtois Straight Through to the Semis
– Pauline Courtois leads after first day