"He looked at me and said, 'I need this, I want this,'" teammate Dax McCarty said. "I knew when I gave him the ball he was going to bury it for us.''
Davies converted the 63rd-minute penalty, added a second goal in the 77th minute and D.C. United defeated the Columbus Crew 3-1 Saturday in both teams' season opener.
Fellow new acquisition Josh Wolff opened the scoring for United, which featured seven new faces.
Robbie Rogers scored on a 79th-minute penalty kick for Columbus.
Davies has been on a long road to recovery since sustaining severe injuries as a passenger in an automobile crash in nearby Arlington, Va., that killed another passenger in October of 2009.
Davies was with the U.S. national team at the time as it prepared for a World Cup qualifying match against Costa Rica.
"It just goes to show with faith, with belief in yourself, that you can achieve the impossible,'' said Davies, who suffered a ruptured bladder, bleeding on the brain, a broken and dislocated left elbow, and broken bones in his right leg, nose, forehead and eye socket.
"Today, I achieved the impossible," he added. "And I've just
got to keep doing it."
Davies, signed on loan from French club Sochaux this offseason, entered just moments after Wolff put United ahead in the 51st minute, and scored his first goal on a penalty kick 12 minutes later.
Chris Pontius earned the penalty when he was taken down by Sebastian Miranda. Davies converted past William Hesmer, who guessed the wrong way. Davies then raised both arms and sprinted toward the corner flag, where he was mobbed by teammates.
Davies had his second 14 minutes later after taking Marc Burch's long ball, escaping Chad Marshall's challenge, circling around Hesmer and finishing into an open net.
That sent RFK stadium's home fans into delirium. And the fan group known as the Barra Brava stayed standing and bouncing until well after the match, as Davies walked over and saluted them for their support.
"It was just one of those nights when things are kind of clicking," United coach Ben Olsen said. "I was happy for him. I was happy for the team that has supported him. And I was happy for the fans. Because I know there (were) a lot of people feeling a lot of joy."
Davies' return comes just a day after the driver in the crash, who was legally intoxicated at the time, was sentenced to two years in prison.