Two MLS mainstays look to lock in a spot in the U.S. Open Cup Semifinals, as the Philadelphia Union take on the New York Red Bulls in the in quarterfinal action on Wednesday night.

The contract, if ratified by DC 33's membership, is retroactive to July 1. After more than a week on strike and several stalled negotiation sessions, leaders of Philadelphia’s largest municipal union came to an agreement with the city, returning some 9,000 blue collar workers to the job.

Members of DC 33 still have to approve a tentative agreement. If they don't ratify it, union president Greg Boulware warns that a strike could resume.

Despite their away struggles, Philadelphia’s form at Subaru Park has been a source of reassurance, as they are currently unbeaten in their last eight league outings at the venue, with the Union’s most recent loss on home soil being a 3-1 reverse to Nashville in mid-March – their only loss in 10 top-flight games in front of their fans this season.

Philadelphia officials and members of the city's union representing blue-collar workers resumed negotiations Tuesday as residents grew increasingly frustrated with garbage piling up on the streets.

ABC News’ Matt Rivers reports on the latest developments as the strike by the city's largest union enters its second week.

Chattanooga FC comes to Subaru Park having earned just three points in their last five games and having not won a game in regulation since May 24. The squad are looking to bounce back after a 1-0 home loss to Chicago Fire FC II that ended their 11-game home unbeaten streak.