ATLANTA -- Sidney Spencer got one shot. She made it count for the Liberty.

Spencer knocked down her lone shot of the game, tying it with 0.2 seconds left in regulation, and the Liberty went on to beat the defending Eastern Conference champion Atlanta Dream, 94-88, in overtime Sunday.

Plenette Pierson scored 25 points to lead the Liberty in the opener for both teams, a rematch of last year's conference finals won by the Dream in a sweep.

Leilani Mitchell made a clinching three-pointer in overtime, but that wouldn't have been possible without Spencer's clutch basket.

Though she played just 5 minutes, the backup forward was on the court when the Liberty set up an inbounds play with 3.2 seconds left, trailing 79-77. Atlanta got a hand on the ball but Spencer wound up with an open 10-footer on the baseline. She swished it to force overtime.

"It was a broken play," new Liberty coach John Whisenant said. "We wanted to get it in to Plenette or Nicole [Powell], and it got deflected to Sidney Spencer. She's a great shooter. She can make an open shot."

The Liberty took advantage of an Atlanta team missing its top player, Angel McCoughtry, who sprained her left knee in camp and didn't dress.

Iziane Castro Marques led Atlanta with 19 points, Sancho Lyttle added 18 points and Lindsey Harding doled out nine assists in her Dream debut.

But Harding also missed a late free throw that could've put it away.

"Angel brings so much to our game," Atlanta coach Marynell Meadors said. "When you take away 25 or 30 points, it affects the rest of the team."