Oxford boss Chris Wilder says his side left Crewe with nothing after creating a hatful of chances before losing 3-1 at Gresty Road.
Shaun Miller's brace and a second-half strike from Ajay Leitch-Smith meant Liam Davis' late effort was nothing more than consolation for the Us.
Wilder said: "That defeat really hurts and is really difficult to take. Not one of my players likes losing and it is going to be a long weekend to get over that one. How we managed to come out of that game with nothing is beyond me. On another day Alfie (Potter) could have had four himself.
"I didn't see a team lacking in spirit, fight or quality, and we created lots of chances. We started well, we were positive and comfortable in possession. Then in the space of five minutes we are 2-0 down in a game we were dominating.
"Their first goal was the result of a lucky deflection and the second looked offside to me. Then they have one attack in the first 25 minutes of the second half and they are 3-0 up.
"Despite that I never felt out of the game and always felt we could get something out of it. I was pleased we never caved in and didn't go into our shells. We were spirited and we will need that attitude to bounce back from this."