While the teams currently sit in 10th and sixth-place respectively, they are within a win away of moving into second position in the standings.
When DC United got the better of New York City FC on matchday one, it appeared that the Washington-based side were set for a much improved 2021 campaign.
However, Hernan Losada has since witnessed his team lose four of their next five fixtures, the latest coming at home to Orlando City by a 1-0 scoreline.
While the Black-and-Red battled their way past lowly Chicago Fire in the previous match, Losada is struggling to take many positives from his team's recent performances.
The setback against Orlando ended United's two-match winning streak at the Audi Field, but Losada will be satisfied with their form on home territory.
None of the first-team squad have contributed more than one goal since the beginning of the campaign with only Edison Flores adding an assist to his record.
As far as Philadelphia are concerned, Jim Curtin will be content with how his players have started the season as they bid to replicate last year's success during the regular season.
That was a different story in April after three games without success, but The Union have responded by collecting seven points over the same amount of fixtures.
Just one goal has been conceded during that period with their latest outing seeing them record a 1-0 triumph over New York Red Bulls.
Cory Burke netted the decisive strike in that fixture, becoming the first player in the squad to score more than once in the MLS.
Jose Martinez is expected to return to the Philadelphia starting lineup after serving his suspension.
DC United still have as many as seven first-team players on the injury list, restricting what Losada can do with his first XI.
Ola Kamara could also be provided with his first start of the season in attack.
DC United possible starting lineup:
Kempin; Alfaro, Brillant, Hines-Ike; Gressel, Felipe, Moreno, Mora; Asad, Flores; Kamara
Philadelphia Union possible starting lineup:
Blake; Mbaizo, Glesnes, Elliott, Wagner; Martinez, Monteiro; Fontana, Bedoya; Santos, Burke
We say: DC United 1-3 Philadelphia Union
While just two points separate the two teams, we cannot ignore Philadelphia's current form and DC United's defensive record. With that in mind, we are backing a convincing victory for the visitors, who are building some momentum in the Eastern Conference.