Washington's defense, led by netminder Michal Neuvirth, shut down Pittsburgh 3-0 at Verizon Center on on Sunday.
Washington won as a -150 favorite, while Over-Under bettors who played UNDER the total of 5.5 were rewarded at the payout window.
Washington got goals from Mike Knuble, Brooks Laich, and Marcus Johansson in the victory. Laich opened the scoring at 18:22 of the first period.
Michal Neuvirth turned in a 22-save effort for the Capitals.
Marc-Andre Fleury stopped 21 of 23 shots for the Penguins, but it wasn't enough to earn the victory.
Washington scored 0 times on 4 chances on the power play, while Pittsburgh went 0-for-2 with the man advantage.
Washington outshot Pittsburgh 24-22 in the game.
Next game, Washington takes its act home to face San Jose looking for another win. For Pittsburgh, they head home to face Columbus.