The Philadelphia Union and Columbus Crew remained in their respective spots in the Eastern Conference after a 0-0 tie at Mapfre Stadium in Columbus, Ohio, on Saturday.
Columbus (13-9-9, 48 points) is in fourth place, a point ahead of the Union (14-12-5, 47 points) with three matches left.
If the standings hold for the remainder of the season, the Crew would host the Union in a first-round knockout match.
Philadelphia's Andre Blake made a lunging save with his right hand in the 90th minute on a strike by Harrison Afful to prevent the Crew from winning its sixth straight at home.
Blake made two saves for his 10th shutout of the season. Zack Steffen did not have to make a save for his 10th shutout as well.
A scoreless first half was not without controversy in the 37th minute when an own goal on Crew defender Jonathan Mensah was overturned after a lengthy video review.
The play started with an overhead ball near the top of the box to the Union's Cory Burke. He outmuscled Crew defender Lalas Abubakar and sent a cross in front of the goal, where it went off Mensah.
However, Burke was ruled to have committed a foul on Abubakar with his shove.
Philadelphia is 6-1-2 in its past nine games, including 4-0-1 on the road. The Union was playing for the fifth time in 15 days and coming off a 3-0 loss at the Houston Dynamo on Wednesday in the final of the Lamar Hunt U.S. Open Cup.
Each team next plays on Oct. 6 with the Crew at Montreal and the Union hosting Minnesota.