After a rather lackluster first half Friday, the Lynx were down four entering the third quarter against the Mercury in Phoenix.

And then Odyssey Sims took over.

In a 29-9 third quarter that turned that four-point deficit into a 16-point lead — and, eventually a double-digit victory — Sims scored 11 points with three assists and two rebounds.

Sims’ final line: 22 points, 10-for-16 shooting, five rebounds, nine assists.

Zero turnovers.

“Her efficiency is what comes to mind,’’ Lynx coach Cheryl Reeve said. “And that’s the ultimate goal with her — recognition of when it’s her time to score, and when to share it for an easy basket.’’

The Lynx are 18-15 heading into Sunday’s regular-season finale against the Sparks in Los Angeles, one of two teams (the other is Washington) the Lynx have not beaten this season. They are in sixth place, one game ahead of Seattle. This much is certain: The Lynx and Storm will meet in a first-round, single-game playoff Wednesday. The where is yet to be decided.

The Lynx will host the game if they beat the Sparks. If they lose, they still host the playoff if Seattle loses at Dallas. But, if the two teams finish with the same record, the game will be in Seattle because the Storm won the season series 3-1.

The Sparks have clinched the No. 3 seed in the league, and a first-round bye. Not able to rise further, the Sparks have relatively little to play for.

The Lynx are on a roll, with a season-best five-game winning streak, one that has guaranteed them a league-record ninth straight playoff berth and the ninth straight season with a winning record. There are a lot of reasons for the Lynx’s recent surge: The steady improvement of rookie Napheesa Collier, center Sylvia Fowles’ strong finish to her 12th season, Damiris Dantas’ regained three-point touch.

And then there is Sims, who continues to pad her résumé for the league’s most improved player award. Acquired in an offseason trade with the Sparks, Sims embraced an opportunity with Minnesota and has led the team in scoring 15 times and in assists 20 times. She has eight games with 20 or more points; Collier is second on the team with three.

So it’s only fitting that Sims will try to secure a home playoff game in the city where she played in 2017 and 2018.

“The big reason is that we have balance,’’ Reeve said about her team’s winning streak. “But she is a big reason for that balance.’’

Sims has five games this season with 20 or more points and eight or more assists, with two of them coming in the past three games. Her game Friday was just the 15th time in league history and the first time this season a player has had at least 20 points, eight assists and no turnovers. Lindsay Whalen (2011) and Seimone Augustus (2012) are the only Lynx players to have done it.

And now Sims will try to get her team a home playoff game in the city she played in the past two seasons. Sims has struggled in the two Lynx losses to the Sparks, committing 11 turnovers and scoring just 18 points in those two games. The Sparks are also the last team to beat the Lynx, on Aug. 20 in Los Angeles. The Lynx began their five-game winning streak two days later.

“We’re just executing better,’’ Reeve said. “And Sims is a big reason.”