(Photo credit: Allan Henry-Imagn Images)

Natasha Cloud tied a season high with 23 points, Breanna Stewart added 18 and the defending WNBA champion New York Liberty took a 76-69 overtime victory over the host Phoenix Mercury in the first game of their playoff series Sunday.

Cloud hit a 3-pointer to open the scoring in overtime and the Liberty scored the first eight points to take control and gain home-court advantage in the best-of-three series that continues Wednesday in New York.

Sabrina Ionescu had 18 points for the Liberty, who are 12-1 when their projected starting lineup plays this season.

Kahleah Copper had 15 points and Alyssa Thomas had 14 points, nine rebounds and eight assists for the Mercury, who could not overcome a 32.5 field goal percentage.

The Liberty, who won one of the four regular-season meetings, have now won four in a row. The Mercury have lost four straight overall as the series shifts east.

Thomas and DeWanna Bonner scored to bring Phoenix within four at 73-69 with 1:16 remaining in overtime, but Leonie Fiebich made a 3-pointer with a minute remaining to push the lead back to seven.

Fiebich had 10 points, and Jonquel Jones had seven points and 12 rebounds.

Stewart appeared to suffer a leg injury when she scored on a driving layup with three minutes remaining in overtime, and she was not on the floor when the game ended.

Phoenix's top three scorers -- Thomas, Satou Sabally and Copper -- shot 14 of 48 from the floor. Sabally, the Mercury's second-leading scorer in the regular season, was 2 of 17 overall and 1 of 10 from 3-point range.

New York had a 48-31 rebounding edge but committed 21 turnovers, tying a season high. Phoenix had 15 points off turnovers.

Phoenix missed its first seven shots in the third quarter before Bonner hit a 3-pointer to close the deficit to 53-51. That was part of an 11-2 run that helped the Mercury to a 57-55 lead after three quarters.

Cloud's layup gave the Liberty a 63-61 lead with 4:17 remaining, and neither team scored again until Copper made two free throws to tie it at 63-63 with 3:02 left.

Bonner's reverse layup on a feed from Thomas made it 65-63 with 1:44 remaining, and Stewart countered within a 6-foot jumper to tie it at 1:31.

Thomas missed a driving layup with 0.9 seconds remaining, and Ionescu's long, contested 3-pointer hit the rim, sending the game into overtime.

--Field Level Media