A road trip that started with unsettled relief and seemed to invite more along the way ended with the coolest presence in the 'pen completing a sweep of the darling Washington Nationals.

Edward Mujica pitched a perfect ninth for his third save in as many days as the Cardinals won 4-2 at Nationals Park on Wednesday afternoon.

The Cardinals completed the three-game sweep of the Nats, who have been picked by many to win this year's World Series. Washington ace Stephen Strasburg allowed three runs -- all in the first inning -- before speeding through the Cardinals lineup. He bought time for an offense that never arrived and, as a result, lost his fourth consecutive start.

Yadier Molina contributed a two-run single in the first inning off Strasburg, and the Cardinals added a run in the eighth with Matt Holliday's RBI infield single.

That was all the pitchers needed.

Jaime Garcia pitched 5 2/3 solid innings and allowed one run on four hits. The one run scored on a groundout. His pitch count swelled and he encountered trouble in the sixth inning, trouble that required the bullpen to rescue him.

A new order of relievers has developed in recent days.

Joe Kelly, so little used earlier in the season, pitched 1 1/3 scoreless innings to bridge the lead between Garcia and eighth-inning righty Trevor Rosenthal. Rosenthal allowed a solo homer to Jayson Werth to momentarily tighten the game, but he recovered to strike out the final two batters he faced.

Mujica has four saves since taking over the ninth.