"The defense stepped up," coach Jay Gruden said. "The first drive was a little scary. Here we go again. But we came back, took it personal and played well."
The game wasn't decided until the final minute, when an apparent 23-yard touchdown catch by Baltimore's Breshad Perriman was overturned by replay. Perriman got his right foot down in the end zone, but his left foot was out of bounds.
That put an appropriate end to a miserable day for the Ravens offense, which was limited to 125 yards after halftime.
"We can't play like that and win," coach John Harbaugh said. "We have to be better than we were today."
Crowder scored Washington's first TD with a sensational run through the middle of the Baltimore punt return team in the second quarter.
The definitive momentum shift occurred minutes later. With the Redskins operating from near their own 3, Ravens linebacker C.J. Mosley intercepted a pass by Cousins at the 13, but lost control of the football while reaching for the end zone. The ball rolled out of bounds in the end zone for a touchback, and the Redskins subsequently moved 72 yards for a field goal and a 16-10 lead.
Washington repeatedly frustrated Baltimore quarterback Joe Flacco, who was 30 for 46 for 210 yards and sacked three times.
The Ravens have lost two in a row - both at home - after opening with three straight wins. All of their games have been decided by six points or fewer.
Baltimore scored a touchdown on its opening possession for the first time this season, on a 7-yard pass from Flacco to tight end Crockett Gillmore.
Crowder responded with the Redskins' first punt return for a touchdown since 2008. But the conversion attempt clanged off the left upright.
Copyright 2016 by The Associated Press