Newcomers Jairo Arrieta and Federico Higuain have helped the Columbus Crew climb into the Eastern Conference playoff race.
The surging Montreal Impact may like their chances of reaching the postseason with Troy Perkins now in net.
With a chance to move up in the standings possibly at stake, the host Crew will try to extend their season-high winning streak to four Saturday night as the Impact go for a sixth consecutive victory.
Acquired from Costa Rican side Deportivo Saprissa in April, Arrieta has five goals and two assists in nine games since his MLS debut July 14.
In just four matches since signing as the Crew's third designated player July 27, Higuain has found the back of the net three times and set up four goals.
One of those two has scored or assisted on seven of the team's eight goals during Columbus' winning streak.
"Federico and Jairo, those guys have a lot of energy up there and creating," rookie defender Josh Williams said after scoring his first MLS goal - assisted by Higuain - in Wednesday's 2-1 win at Philadelphia. "It's contagious and everyone wants to be a part of it."
Williams won't be part of Saturday's lineup after getting a red card against the Union, but the Impact should keep an eye on Eddie Gaven, who has three of his team-high seven goals since Higuain arrived, including the game-winner late in stoppage time Wednesday.
Columbus, 3-0-2 since a 1-0 loss at D.C. United on Aug. 4, is riding its longest winning streak since a four-game run May 8-23, 2010.
If coach Robert Warzycha's club can win its second at home over Montreal - the Crew defeated the visiting Impact 2-0 on March 24 - Columbus (11-8-6) may have a chance to leapfrog D.C. and Chicago in the East standings.
Montreal (12-13-3), though, has its sights set on the same feat. The Impact are 2-10-1 on the road, but the expansion club arrives at Crew Stadium in the midst of a 7-2-0 overall stretch, which started with a 2-1 home win over Columbus on July 8.
"I think we're both on a good run right now," Impact captain Davy Arnaud said. "We obviously know how important this game is in terms of what it's going to mean for the postseason."
Montreal has just six games left - the Crew have nine remaining - but another strong effort by Perkins could help the Impact move ahead of Columbus.
Since arriving from Portland via trade Aug. 7, the Ohio native has posted two shutouts and yielded one goal - a penalty kick in a 3-1 victory over league-best San Jose on Aug. 18.
The Impact have converted all nine of their penalty chances, with leading scorer Patrice Bernier recording his sixth - the most in MLS since Jaime Moreno in 2009 - in last Saturday's 3-0 win over D.C.
"I've never seen a season like this where one team has had so many penalty kicks," said Bernier, whose penalty kick in the 89th minute July 8 was the difference against the Crew. "As long as we're winning, I'm happy."
The Impact will likely be facing goalkeeper Matt Lampson for the first time, with Columbus starter Andy Gruenebaum expected to miss a second straight match with a lower back strain.
Crew defender Julius James won't play after being suspended one game by MLS for what the league termed "violent conduct" against Philadelphia this week.