Buehrle threw a six-hitter — his 11th career shutout — and Toronto scored four runs in the first inning to close the interleague series against Washington with an 8-0 victory Wednesday night.
Buehrle (7-4) worked fast and effectively against the NL East leaders, needing only 93 pitches for his first shutout since 2013. Both of the 36-year-old's starts on the concluded road trip resulted in complete game wins. He also had a single Wednesday.
"That was a masterpiece," Blue Jays manager John Gibbons said. "It always seems like when we need something, he steps up."
Washington put runners on base in each of the first six innings against Buehrle, but rarely threatened, twice hitting into inning-ending double plays. He walked one and had two strikeouts in a game that lasted a crisp 2 hours, 13 minutes.
"He knows how to pitch," said Nationals outfielder Bryce Harper, who went 2 for 4 with a double. "He locates very well and keeps guys off balance. That's what he did tonight."
Harper batted .360 with 13 home runs and 28 RBIs in May.
The first four batters reached against Taylor Jordan (0-2), who made his first start this season for the Nationals with Stephen Strasburg sidelined.
Jose Bautista, Chris Colabello and Kevin Pillar had RBI singles in the first inning. Bautista hit a solo home run in the eighth. Jose Reyes had three hits and drove in two runs.
"It helps," Buehrle said of the early support. "You can go out there and realize if you make a mistake ... it's not the end of the world. You can go out there and kind of get in a groove."
The teams split Tuesday's rain-forced doubleheader with the Blue Jays winning the nightcap 7-3.
Toronto had lost 16 of 21 road games before consecutive victories in Washington.
Jordan allowed a career-high seven earned runs and 10 hits in six innings against the highest-scoring offense in the majors.
Buehrle's previous shutout was a two-hitter against Houston on July 25, 2013.
"He was hitting the corners really well," Toronto catcher Dioner Navarro said. "He's been doing this for so long. He makes my job a lot easier."
Including the final four innings of Tuesday's loss, Washington went the last 13 innings of the series without a run.
Buehrle picked up his 30th career win in interleague play, the most among active players, and 206th of his Major League career.
By comparison, Jordan fell to 1-7 in 15 career starts.
Recalled from Triple-A Syracuse on May 24, the right-hander made his season debut in relief of Strasburg on Friday at Cincinnati. Strasburg (neck tightness) was placed on the 15-day disabled list the following day.
Colabello's first-inning single extended the outfielder's career-high hitting streak to 14 games.
Blue Jays: Edwin Encarnacion remained sidelined with a left hamstring injury. Gibbons said the 1B was available to pinch hit and hoped to use him as the DH on Friday against Houston.
Nationals: CF Denard Span went 0 for 4 in his return to the starting lineup after sitting out Tuesday's doubleheader. Washington's leadoff hitter left Sunday's loss at Cincinnati with a sore right knee.
Washington swept the NL monthly awards as Max Scherzer (5-1, 1.67 ERA during May) was selected Pitcher of the Month and Harper was Player of the Month. Scherzer and Harper are the first teammates to win the awards in the same month since Milwaukee's Ryan Braun and CC Sabathia in July, 2008.
Blue Jays: Toronto returns home for a three-game series against Houston. Aaron Sanchez (4-4, 3.88 ERA) faces fellow RHP Roberto Hernandez (2-4, 4.92) in Friday's series opener.
Nationals: Gio Gonzalez (4-2, 4.73) faces Cubs RHP Jake Arrieta (4-4, 3.18). Washington won two of three in Chicago last month.