And it wasn't any garden variety victory. The conditions got so bad early that there was a brief delay to turn on the stadium's lights, and the rain turned into a steady downpour in the seventh inning. Guthrie buckled down and escaped a jam in the seventh, coaxing a ground ball from Aaron Hill to end the threat.
"My dad used to say I was a good rain pitcher," said Guthrie. "I think of late I've had some poor rain outings, so it did feel good to be in those conditions and come out of there with a positive result."
Indeed, the skies got dark and the rain cut through Camden Yards in the seventh inning, prompting a mound visit from pitching coach Rick Kranitz to make sure Guthrie could get through the frame. Guthrie waved off those concerns and slogged through the inning to earn one of his most satisfying results all year.
"I don't know how he did it," said manager Dave Trembley. "I don't know how he could feel the ball. I really don't know who has the advantage, the pitcher or hitter. But he pitched in it. I would think it was on his side."
"It was a real tough little situation," added Guthrie. "I could not feel the ball very well. The tack that you get from the rosin bags, with the water coming down made it worse than I think if you didn't have the rosin bag there. So I couldn't really feel it. But to get that big out there and Aaron Hill just mishit that pitch enough to get that ground ball and get through that inning. And then we get the big insurance runs. That was a huge play for us."
Guthrie, whose team had lost six of his past seven starts, was at his shakiest early in the win. The right-hander gave up two hits in the first inning and didn't do that again for the rest of the game. Guthrie wound up charged with one run. He hadn't allowed less than three earned since his second start of the season.
And in that stat, you can find perspective. Baltimore's staff ace has allowed two earned runs or less in two of his first 10 starts. Last year, he gave up two earned runs or less in 17 of his 30 outings. Still, Guthrie (4-4) remains confident and said that he hasn't really questioned why he's gotten off to a slow start.
"I haven't felt far enough away that I'm necessarily looking for a lift," Guthrie said. "I'm trying to have some quicker pitch innings -- especially at the beginning -- because I felt like I was in a trend where I've gotten off to slow starts with the high pitch-count and been able to roll through the last few innings. I'd like to be able to feel that in the beginning of the game, and although they got the one run, the pitches were much more efficient."
Toronto (27-21) used a leadoff single, a stolen base and a two-out hit to score the game's first run. The Blue Jays pushed runners to scoring position in each of the next two innings but were stopped short by Guthrie. Baltimore's bullpen allowed two hits, and closer George Sherrill worked the ninth for his 10th save.
Meanwhile, the Orioles (19-26) tied the game in the first inning on a double play. Baltimore stranded three runners in the second inning and pulled ahead in the fourth, when Aubrey Huff doubled and scored on Gregg Zaun's single. It was a one-run game from there until Baltimore scratched out two runs in the seventh.
"I don't know if it's more than a regular win," said second baseman Brian Roberts. "But Toronto has given us some hard times in the last couple years and certainly they are playing good baseball this year. So for us to beat a good team in our own division, yeah, I think that is something we can build on a little bit."
Roberts overcame an injury early in the game to play a key role in the late innings. The two-time All-Star suffered a left shin contusion on a play at second base in the second inning, but elected to play on it. Roberts wound up tripling in one run in the seventh and scoring another before the Orioles pulled him early.
The veteran infielder is listed as day-to-day but expects to play in Tuesday's game.
"He had a pretty good bruise on his shin," said Trembley. "I asked him about maybe the fourth or fifth inning how he was doing and it was stiffening up on him. He was getting ice between innings on it. Boy, he sure came up with a big hit and ran real good home-to-third, but I saw him favoring it then and that was enough."
And it was more than enough for Guthrie, who happily yielded to the bullpen. The former first-round Draft pick stepped up and pitched a statement game on Monday, allowing the Orioles to enjoy a victory and just forget about the holes in their rotation. For one day, Baltimore's rotation was the healthiest aspect of the team.
"That's what the No.1 guy does," said Zaun. "They have a lot of responsibility, more than just pitching games. They're out there to set the tone for the rotation, end losing streaks and whatnot. That's a lot to heap on a guy, but he's our guy. He's the one, outside of Koji [Uehara], that's still in the rotation from the beginning of the season. We're definitely going to need him to stay healthy and stay in the rotation and keep contributing."
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.