"It was a great win, the bullpen did a good job, and the offense -- the kid [Bryce Harper] keeps hitting the ball," Nationals manager Davey Johnson said.
Harper was front and center in the Nationals' victory for the second consecutive night.
Harper, who collected three hits in Monday's opener and reached base four times, smacked a base hit to right field his first at-bat Tuesday, and got the Nationals on the board in the third inning in a big way.
The 19-year-old took the first pitch he saw from Blue Jays starter Henderson Alvarez and crushed it to right-center field -- a mammoth blast, his seventh of the year, that put the Nationals ahead, 1-0.
"I just felt really good up there," said Harper, who finished the game 3-for-4, increasing his average to .307. "At the beginning of the year, I usually struggle, but once I get going, it's scary -- I've always said that. ... I was going up there swinging out of my shoes first pitch, I had already made my mind up."
The next inning it was Danny Espinosa's turn.
With one on and two out, Danny Espinosa -- who doubled in his first at-bat -- took Alvarez to straightaway center field to increase Washington's lead to 3-0.
Jhonatan Solano added the Nationals' third homer of the night -- and third off Alvarez -- with a solo shot to left field, the first of his career, that put Washington up, 4-2, in the seventh.
"Sweet, I got it," Solano said when asked what the feeling was like. "It's a lot of emotion, I'm happy."
Alvarez, who lasted seven innings, fell to 3-6 on the season and has allowed the most home runs in the Majors since May 15.
"I feel like I'm throwing the ball well," said Alvarez, who lasted seven innings and allowed four runs on nine hits. "I don't feel like I need to change anything. Just try to keep the ball down."
Nationals starter Chien-Ming Wang was shaky throughout the night but improved to 2-2 on the season.
Wang battled control problems throughout the game, but he kept finding his way out of jams until Jose Bautista made him pay in the fifth inning.
The 32-year-old Wang served up a 2-2 offering that Bautista deposited into the seats in left for a two-run homer, his 18th of the season, that cut Washington's lead to 3-2.
After getting through the rest of the fifth, Wang's night was done.
The right-hander, who left with a 3-2 lead, surrendered four hits, allowed five walks, hit one batter, threw a wild pitch and struck out five. Wang issued a season high in walks and strikeouts, while the four hits were a season low.
"I feel kind of better today, but the thing that happened today was that the ball sometimes sank too much," Wang said through interpreter John Hsu.
It wasn't the most efficient game for Wang, who said he was having some mechanical issues of getting his body too far in front of his arm, but it was effective enough for Washington, and the Nationals' bullpen was able to take care of the rest.
Ross Detwiler, Craig Stammen, Sean Burnett and Tyler Clippard combined to throw four scoreless innings of relief and allowed just one runner to reach base.
Stammen allowed a double by Bautista in the seventh inning, but Toronto couldn't do anything other than that off Washington's crop of relievers.
Clippard struck out a pair in the ninth to earn his ninth save of the season.
"It has been awfully good all year long," Johnson said about the bullpen. "We have a lot of good options out there. ... Tremendous pitchers, they are doing a heck of a job."
The first-place Nationals will turn to Stephen Strasburg as they look to go 6-0 on a road trip for the first time in franchise history in Wednesday's series finale, and they have won seven of their past eight games to reach a season-high 14 games over .500 at 37-23.