Both teams advanced to this phase of the competition in heart-stopping fashion, with the Crew winning 4-3 on penalties versus New York City FC and Philly claiming that same result in a shootout against Mazatlan.
Match preview
Another resilient performance for Columbus has them one win away from a Leagues Cup final appearance for the first time in club history.
Their road to the semi-finals has not been easy, with Crew winning their two matches in this tournament despite conceding first each time.
While they managed to advance in their previous encounter, this team have not won a match in normal time when netting just once since defeating the Houston Dynamo 1-0 in CONCACAF Champions Cup (CCC) action in March.
Wilfried Nancy's men have never lost a Leagues Cup knockout fixture on home soil within 90 minutes, with that lone defeat coming in the round of 32 last year versus Minnesota United on penalties (4-3).
The last time they hosted a semi-final game, the Crew came away with a 2-1 victory over Monterrey in April, advancing into the final of the CONCACAF Champions Cup 5-2 on aggregate.
Columbus have historically beaten four opponents from Major League Soccer (MLS) in this competition and have never been shut out in any of those encounters.
A pesky Mazatlan side made life very difficult for the Union on Saturday, but the home team held their nerve in the penalty shootout.
Because of that, they are back in the semi-finals of this tournament for a second successive campaign, with a shot at redemption after losing 4-1 to Inter Miami at this stage last year.
Jim Curtin's men have failed to advance from their previous three successive semi-final appearances in either the Champions Cup or Leagues Cup.
Wednesday will only be the second time they play a knockout fixture in this competition away from Subaru Park, with the Union claiming a 4-2 victory at FC Cincinnati in the round of 16 this year.
That triumph ended a four-match losing run for them away from home across all competitions, with their previous victory as the visitors occurring at Gillette Stadium against the New England Revolution in May (3-0).
They are unbeaten in their last seven meetings against Columbus, though they have never claimed a victory at Lower.com Field.
Columbus Crew Leagues Cup form:
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Columbus Crew form (all competitions):
Philadelphia Union Leagues Cup form:
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Philadelphia Union form (all competitions):
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Team News
Over the weekend, Columbus were without Taha Habroune, who has not played since returning from the CONCACAF Under-20 Championship, while Evan Bush remains sidelined due to a wrist injury.
Cucho Hernandez scored the equaliser for his side versus NYCFC in the quarter-finals, Patrick Schulte replaced Nicholas Hagen in goal and made one penalty stop, while Santiago Rodriguez of New York City sailed his spot kick over the bar, cancelling out the miss by Diego Rossi.
Philly are not expected to have Isaiah LeFlore available for this encounter as he is still recovering from a right knee injury, while Tai Baribo will not be available after receiving a pair of cautions in the opening half versus Mazatlan.
Mikael Uhre had the only strike for Philly this past weekend, while Andre Blake was the hero with two penalty stops to help his side advance.
Columbus Crew possible starting lineup:
Schulte; Moreira, Camacho, Cheberko; Farsi, Zawadzki, Nagbe, Jones; Ramirez, Rossi; Hernandez
Philadelphia Union possible starting lineup:
Blake; Harriel, Glesnes, Elliott, Wagner; Flach; Q. Sullivan, McGlynn; Gazdag; Donovan, Uhre
We say: Columbus Crew 1-0 Philadelphia Union
This is usually the stage where we see the Union struggle, and facing a side as balanced as the Crew, we do not believe the visitors have enough firepower to advance.