The Angels' offense finally broke through in the eighth on a crucial error from Nationals shortstop Ian Desmond. Albert Pujols led off the frame with a soft dribbler up the middle that Desmond had trouble with.
Tyler Clippard (1-2) struck out Ian Stewart in the next at-bat, but Pujols stole his first base of the season to move into scoring position. Howie Kendrick's infield single put runners at the corners and Brennan Boesch popped out to Desmond for the second out of the inning.
Ibanez swung through Clippard's first offering, then blasted the next pitch into the gap in left-center that cleared the bases and gave the Angels a three-run cushion.
Fernando Salas (1-0) earned the win in relief of Garrett Richards, who surrendered just one hit over six innings of work, but walked four, hit a batter and was charged with one run. Although Ernesto Frieri gave up a run, he struck out the side in the ninth and nailed down his second save of the season.
Nationals starter Tanner Roark pitched 6 2/3 scoreless innings and allowed seven hits with five strikeouts and two walks. Ian Desmond hit his fourth homer of the season in the ninth off Frieri and Adam LaRoche added an RBI in the setback.