Oxford chief exec Tim Williams was full of pride after their League One promotion playoff final victory over Bolton Wanderers.
Josh Murphy struck twice at Wembley as Oxford won 2-0. It marks a return to the Championship after a 25 year absence.
Williams told BBC Sport: "This is the best day in my career and in my time in football.
"Everyone talks about the sea of yellow at Borussia Dortmund, but today that was the Oxford fans, and it was utterly overwhelming.
"This is a club going places and today proves it.
"We're a Championship club and it's bizarre to say, so I'll say it again: we're a Championship club!
"And now the hard work begins."