DeMya Walker added 11 points for New York (5-9), who had lost four of its previous five.
Ann Wauters and Tina Thompson scored 10 points each for Seattle (6-8), which snapped a five-game winning streak. The Storm shot just 32 percent from the field (19 for 59), including 4 for 22 on 3-pointers.
Sue Bird's third 3-pointer of the game and first since about 4 minutes into the game capped a 7-1 run that pulled the Storm to 56-48 heading to the fourth quarter.
However, Pondexter and Kara Braxton had consecutive layups to restore the Liberty's double-digit lead, 65-52, with 6:17 to go. Seattle got no closer than 10 again.
Nicole Powell's jumper with less than 43 seconds to go closed the scoring and gave New York its largest lead of the game.
Carson had a bank shot and Pondexter made a layup in the opening minute of the third quarter to extend the Liberty's eight-point halftime lead to 35-23.
Thompson's layup cut the lead to 39-32 with 7:05 left in the period, but New York scored the next six points and Pondexter's 3 with 4 1/2 minutes to go pushed the Liberty's advantage to 50-36.
The Liberty's second 9-0 run of the game, started by Carson's two free throws with just more than a minute remaining in the first quarter and capped by Kia Vaughn's layup with 8 minutes to go in the half, gave them a 20-12 lead.
Camille Little's three-point play pulled Seattle to 24-21 near the midpoint of the second quarter, but Pondexter followed with a 3 and Vaughn had a turnaround jumper to push the Liberty's lead to eight with 3 1/2 minutes to go in the period.
The Liberty led 31-23 at the break. Seattle had its lowest first-half scoring total of the season while shooting 22 percent (7 for 32) from the field, including 2 for 12 on 3s. The Storm also committed 15 turnovers, leading to 11 points for the Liberty.
Bird made two 3s nearly 2 minutes apart to give the Storm an 8-2 lead with just under 6 minutes left in the first quarter.
The Liberty then scored the next nine points, taking the lead on Vaughn's fast-break layup with 3:35 to go. Pondexter made two free throws 25 seconds later to cap the spurt and push New York's advantage to 11-8.
Ewelina Kobryn had a jumper and Shekinna Stricklen made two free throws to put the Storm ahead by one with 1:16 left in the first. However, Carson's two free throws 12 seconds later put the Liberty ahead for good.