With Washington trailing 17-13, backup quarterback Colt McCoy hit tight end Derek Carrier for a 9-yard score on the first play of the fourth quarter. After an interception of A.J. McCarron by Fish Smithson, Dustin Hopkins added a 26-yard field goal with 3:39 remaining.
Quarterback Jeff Driscoll then drove the Bengals inside the Redskins' 10, but on fourth-and-goal from the eight, his pass was incomplete in the end zone.
Redskins quarterback Kirk Cousins played the first half and one series in the third quarter, completing 10 of 19 passes for 109 yards and one interception. McCoy was 8 of 11 for 76 yards.
Running back Rob Kelley had 10 carries for 57 yards.
Andy Dalton was 8 of 13 for 70 yards in the first half, while McCarron was 7 of 13 for 82 yards. A.J. Green had four catches for 43 yards and Alex Erickson had three for 51 yards. Running back Joe Mixon gained 31 yards on eight carries.
The Bengals took a 7-0 first quarter lead on Jeremy Hill's 3-yard run.
With the score 7-3, Bengals linebacker Vontaze Burfict intercepted a Cousins' pass and returned it 62 yards for a touchdown.
Washington answered right back. Kelley started the drive with a 21-yard run, and his 1-yard run capped a 10-play, 75-yard drive to pull Washington within 14-10 and a Hopkins field made it 14-13 at halftime.
The dress rehearsal featured the 2017 debut of players from both teams who had been out for varying lengths of time.
Pass rusher Junior Galette suited up for Washington after missing the 2015 and 2016 seasons with a pair of Achilles' tendon tears, and the first two preseason games with a hamstring strain.
Tight end Jordan Reed, back after missing training camp and two preseason games with a toe injury, had two catches for 12 yards.
For the Bengals, first-round draft pick John Ross, who had labrum surgery following the NFL Scouting Combine, saw his first action and ran the ball once for eight yards; and running back Giovani Bernard made his first appearance in a game since tearing his ACL last November, carrying four times for 25 yards.