The Sparks' final was a preview, or so they hope.

The Sparks trampled the Phoenix Mercury, 89-55, in their last game of the regular season. The same teams will play in the first round of the playoffs in a best-of-three series that begins Thursday.

The Sparks were dominant from the beginning, opening up a 19-point lead in the first quarter and expanding it to as many as 38 points. The Sparks forced the Mercury to commit 20 turnovers, and held it to 34.5% shooting from the field.

The Sparks, however, aren't exactly using this game as a measuring stick.

"We're by no means thinking that it's going to be like this come the playoffs, so we definitely have to come ready to play," said Candace Parker.

That's a valid point considering the Mercury was playing without Candice Dupree (tight hamstrings), and was missing Diana Taurasi for much of the game after she took a knee to a quadriceps in the second quarter, then rested the entire second half for what the team called "precautionary reasons."

Sparks Coach Carol Ross didn't mince words when she was asked what Sunday's game taught her about the Mercury.

"Not much," Ross said. "I know they're much better than the way they played, but, at the same time, we just wanted to make sure we're better and we're moving forward."

Five Sparks players finished in double figures, including Parker (16 points), Jantel Lavender (16 points), Lindsey Harding (12 points), Kristi Toliver (12 points) and Nneka Ogwumike (12 points). No one on the Mercury scored in double figures.

"I think it's great for our team," Parker said. "I think that's been our thing for this whole year. Everybody can step up; everybody can do well at any given moment. Once you take away one thing, we have other things that we can come with."

The win tied the teams at 2-2 in their season series. The Sparks beat the Mercury, 88-76, on July 14. The Mercury won, 97-81, on June 14 and 90-84 on July 18.

The Sparks, who have clinched second place in the Western Conference for the second consecutive year, will host Game 1 of their playoff series against the third-seeded Mercury on Thursday at 7 p.m. Game 2 will be in Phoenix on Saturday. And Game 3, if necessary, will be in L.A. on Sept. 23.

The Sparks finished the season tied with Minnesota for the best home record in the league (15-2). Ross said that even though Sunday's game didn't have any playoff implications, the win was very important to the team.

"We wanted to leave our fans with a good taste in their mouths to finish the regular season."

melissa.rohlin@latimes.com