Chris Wilder felt Oxford United were unlucky to lose by such a big margin after their 4-0 Capital One Cup defeat to Charlton.
The U's, who racked up an impressive 4-1 win at Portsmouth in their season opener, were second best for most of a difficult night at The Valley on Tuesday.
Wilder said: "It was a little bit (harsh). We were playing against a good side with some Championship players.
"They (Charlton) freshened it up and they've got players out there who want to get in the side on Saturday.
"It was a good test for us and I'm delighted that we chucked a couple of our kids in. I thought they were first class and didn't disgrace themselves.
"The game became open and obviously that suited them. We left ourselves open on the break.
"We were disappointed in a couple of the refereeing decisions and disappointed not to score on the night as we had decent chances.
"We're out now, but we look forward to Saturday when we have a chance to go top of the league.
"People looking at the result will think we've had a mauling, but as soon as we get off the bus we'll forget about it."