Matthew Tipton and his players have found a way to win on nine of the 12 fixtures under his management.
The Championship leaders’ ability to secure six wins from eight unbeaten league appearances in that period could provide a blueprint to success on Saturday.
“We have to be professional as there is an expectation on us to win given home advantage against Crewe as a Mid-Ulster Football League club,” said Tipton. “But we have done our homework and will treat Crewe with respect.
“I’ve read Crewe talking about a gameplan to stifle us but at times in the league we have faced the same scenario and had to be patient to come up with a solution to break teams down.
“Hopefully those past experiences will help us.”
United’s first appearance in the last 16 arrives with the Crewe squad stretched due to player exits, suspension and injury.
“It’s not great but it is what it is,” said Crewe boss Peter Kennedy. “We won’t make too many excuses and we will go down there looking to make it difficult for them.
“The lads have done really well to get this far and whatever happens, we’re going to enjoy it.”