Early on it was Crewe that looked sharp and they took the lead in the tenth minute when Luke Varney was on hand fire home after Neil Cutler had parried a low shot from Nicky Maynard in to his path.
Despite the blow, United rallied with Delroy Facey shooting against the post, before they grabbed a leveller after 32 minutes.
Nine minutes later the hosts went in front when the outstanding Partridge steered the ball home following Hoskins' sublime flick.
In first-half stoppage time, United went further ahead when Lee Williamson netted his fifth goal of the season from the spot after Michael Higdon's crazy handball.
The only sour point for the hosts came late on when Bopp was dismissed after picking up his second yellow card for a foul in the centre circle.