Washington beat Atlanta 6-4 and essentially put to rest any thought that there is still a serious race for the National League East title, opening a nine-game divisional lead and also damaging the Braves' wild-card ambitions.
Washington's Adam LaRoche singled in a run in a four-run first innings and added another RBI single in the second.
Elsewhere, Detroit won 4-2 at home against Kansas City, with the key moment coming in the fifth inning as Tigers pitcher Max Scherzer worked his way out of a bases-loaded jam.
San Diego arrested a six-game losing skid by winning 6-3 at the Dodgers, with Andrew Cashner pitching seven strong innings to win for the first time since mid-April.
Cincinnati's Devin Mesoraco homered and drove in three runs to lead the Reds to a 9-5 win against St. Louis, ending a six-game run of defeats.
Baltimore's Alejandro De Aza hit two homers and Adam Jones added another to power the Orioles past Boston 4-1.
Oakland 11-2 Chicago White Sox
Miami 6-3 Milwaukee.
LA Angels 9-3 Texas
Tampa Bay 4-3 New York Yankees
Philadelphia 4-2 Pittsburgh
Toronto 9-2 Cubs
San Francicso 4-1 Arizona
Minnesota 4-3 Cleveland
NY Mets 2-0 Colorado