Montreal has Atlanta United’s attention ahead of Sunday’s game at Mercedes-Benz Stadium for one big reason: playoff possibilities.

If Chicago loses at Philadelphia on Saturday and Atlanta United defeats Montreal, the expansion team will move into third place, with 49 points to the Fire’s 48, in the MLS Eastern Conference.

Montreal has 39 points and is in seventh place – one spot outside the playoffs – and needs to win to continue to put pressure on the sixth-place New York Red Bulls (42 points) and fifth-place Columbus (44 points), which will play each other Saturday.

“It’s a big game,” Atlanta United captain Michael Parkhurst said. “They are fighting for their lives right now, fighting for that playoff spot. We think we can distance ourselves nicely against them if we are able to get a draw, or hopefully a victory.”

The seeding is important.

The third- and fourth-seeded teams will get to host playoff games. Atlanta United is 9-2-2 at home this season, including 3-0-1 at Mercedes-Benz Stadium, where it has scored 17 goals.

The first-round playoff games will be played Oct. 25 or 26. The first leg of the semifinals will be played at the site of the higher seed Oct. 30 or 31. The second leg will be played at the home of the lower seed Nov. 5. The Eastern Conference championship’s first leg will be held at the home of the higher seed Nov. 21, with the second leg Nov. 28 or 29.

The MLS Cup will be held Dec. 9 at the site of the competing team with the best regular-season record.

Sunday’s game won’t be easy, but could be exciting because Atlanta United’s Josef Martinez and Montreal’s Ignacio Piatti have each scored 17 goals and are trying to chase down NYCFC’s David Villa for the league lead.

A goal by Piatti helped Montreal defeat Atlanta United 2-1 on April 15 in a game that manager Gerardo Martino described as two games.

The Five Stripes controlled the first half until the final minutes when Leandro Gonzalez Pirez received what Martino said was an unfair red card that resulted in a converted penalty kick by Piatti. The red card was rescinded by the league’s disciplinary committee after Atlanta United appealed. Anthony Jackson-Hamel scored the winning goal in the final seconds after deflecting a shot.

“Generally, we played a great game,” Gonzalez Pirez said. “But we lost on the last play. We came home said, but Sunday is another game.”

From their first meeting, which Montreal won 2-1, the Impact have changed formations from a four-man backline to a five-man back line. The change helped Montreal snap a four-game losing streak and hand Toronto its first loss at home this season Wednesday in a 5-3 win.

The tactical change won’t change Atlanta United’s approach of pressing, forcing turnovers and beating teams with counter-attacks.

But Montreal switching to a five-man back line should open space in the middle of the pitch that Atlanta United can take advantage of when it wins the ball. Martino said it will be key for Atlanta United’s players to get into the right spots to attack.

“For us to be to control the game we have to be able to dictate the rhythm of the game,” Martino said.