Bristol Rovers boss Paul Buckle felt his players shot themselves in the foot after a comprehensive 3-0 defeat at Oxford.
James Constable scored either side of a Peter Leven penalty as the Us battered Rovers in front of more than 9,000 - their biggest gate of the season.
Buckle said: "We were looking good but it's individual errors that have killed us.
"We were doing well and I couldn't see a goal coming for Oxford. Then Constable gets in and we're on the back foot. In the second half we got back into the game only to give away a penalty. So we beat ourselves.
"When we came out in the second half, I was quite pleased with the way we passed the ball and how we were creating chances. But individual errors are costing us. We've got so much work to do.
"We've had a lot of things go against us, we're in a tough spell. We gifted them the second goal with the penalty, and then lost possession in the middle of the park for their third. We've got to start keeping clean sheets, that's got to be the first priority."