Hudson hit two home runs -- including a tiebreaking two-run shot in the eighth inning -- and Toronto beat Washington 9-5 Sunday, snapping the Nationals' 12-game home winning streak.
"When the pitching's going great, the hitting's not going well. When the hitting's not going well, the pitching is. ... It's just great to get that big win," said Hudson, who had been 0-for-8 in the weekend series before homering in the fifth for the Blue Jays' first hit.
Eric Hinske led off the eighth with a double to right, and one out later Hudson hit his sixth homer to right-center off Luis Ayala (6-4).
After watching his team fall below .500 on Saturday, manager John Gibbons was pleased to see the Blue Jays avoid a sweep in their first trip to Washington.
"These guys have fallen before .500 before, and then they bounce back up," Gibbons said of his 38-38 club. "Hopefully this'll be the start of something. We beat a good team today."
Justin Speier (1-1) got the final two outs in the seventh, Miguel Batista pitched two innings for his 14th save and the Blue Jays halted a six-game road losing streak.
Junior Spivey homered and Vinny Castilla had two RBI for the Nationals, who had won three straight and five of six overall.
Washington fell a game short of matching the franchise record for consecutive home victories, set by the Montreal Expos from Aug. 28-Sept. 15, 1979.
"It just didn't happen for us today," Nationals outfielder Marlon Byrd said. "We've been rolling, so this was a little out of character."
Hudson's solo homer in the fifth started a four-run rally that erased the Nationals' 2-1 lead. Shea Hillenbrand put the Blue Jays up 4-2 with a two-run, ground-rule double into the corner in right field, chasing starter Tony Armas.
"I can't explain it," Armas said. "I don't know what happened. I let my team down. I left everybody down."
Hector Carrasco came on, hit Aaron Hill with a pitch to load the bases and then threw a run-scoring wild pitch.
Washington tied at 5 it on Jamey Carroll's fielder's choice in the sixth, and Castilla's two-run double off Justin Speier in the seventh.
"To tie it at 5-5 and go right back out there and give it up, that's tough," Washington manager Frank Robinson said. "That one was the one that was kind of devastating."
Toronto scored twice in the ninth on Vernon Wells' RBI single and Hinske's sacrifice fly.
Toronto took a 1-0 lead in the first, scoring an unearned run without getting a base hit. Reed Johnson drew a leadoff walk and scored when Hillenbrand hit a one-hopper to Armas, whose soft toss to catcher Gary Bennett was fumbled.
Washington took the lead with two runs in the third. With one out, Spivey hit a Gustavo Chacin pitch over the wall in left-center for his seventh homer. Jose Guillen doubled down the left-field line, stole third and scored by beating second baseman Hudson's throw home on Nick Johnson's fielder's choice grounder.
Armas gave up five runs -- four earned -- and three hits in 4 2/3 innings. He walked three and struck out five.
"He just lost focus and concentration," Robinson said when asked why Armas unraveled so quickly.
Chacin gave up three runs and five hits, with three walks and two strikeouts. He left with a 5-2 lead after 5 1/3 innings.
- The Nationals finished interleague play 12-6, while Toronto was 8-10.
- 1B Nick Johnson walked in the first and has now reached base via a walk, hit or hit by pitch in 69 of Washington's 74 games. He left the game after scoring the tying run in the seventh with a bruised right heel and was sent to the hospital for precautionary X-rays and will be reevaluated Monday.