"They are doing fantastic. Hopefully we can get the win," Rooney said. "It's great. You see the atmosphere back home. There are billions watching it. Hopefully we can get through and go on to the final."
Manager Gareth Southgate's England squad will face Croatia in a semi-final for a berth in Sunday's championship match against either France or Belgium.
"For the players and Gareth, I wish them massive good luck. They are making us all proud," Rooney said. "Hopefully they can get that one step further and get to the final and bring the Cup home.
"I've enjoyed all the buzz coming out of this. We're enjoying it and we believe."
DC United, which last won the MLS title in 2004, has the worst record in the league with two wins and five drawn from 14 matches. But there is renewed hope in Rooney and the new 20,000-seat Audi Field.
"I can't wait. I'm looking forward to it," Rooney said of Saturday's match.
Rooney, wearing a black shirt with a DC United logo, thanked fans gathered at the facility.
"On the first day when I landed at Dulles airport, the reception you gave me was something I will never forget," Rooney said.
"I've come here to help this team win, to move forward and hopefully in the next few years we can climb the table and win titles and bring trophies to this wonderful new stadium.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)