Cecil (4-9) gave up two runs, one unearned, in 7 2-3 innings while striking out a season-best nine, but it wasn't enough as the Jays fell 2-0 to the Baltimore Orioles.
Baltimore's starter Jeremy Guthrie (7-17) was just a bit better, scattering three hits over seven innings while Vladimir Guerrero and Nick Markakis drove in the runs for the Orioles.
Cecil hasn't won since defeating the Texas Rangers in consecutive games on July 24 and 29. The first win was a shutout of the American League West leaders.
Although Cecil hasn't won a game in eight chances, he's starting to see some positive signs.
"This game I felt like my mechanics were there," the Blue Jays left-hander said. "I told (pitching coach Bruce Walton) after my last bullpen I said 'I felt like I was throwing like last year,' staying back over the rubber as long as I could and just driving forward."
On most nights the Jays starter would have picked up the win Orioles manager Buck Showalter said.
"(Cecil) was really good," said Showalter. "The key to being in the ball game is the pitching job our guy did to match up with him because you're not going to beat him unless you get a similar outing from your guy."
The first run of the game came on Guerrero's two-out single in the sixth and was unearned after an error by second baseman Kelly Johnson on a failed double play attempt.
"He hit a great pitch," Cecil said. "Curveball down. That's just the type of hitter he is. Seems like you can never fool him. Tried to be really careful. Put a lot of good pitches to him, but, oh well."
Robert Andino led off the sixth with a single. He was forced at second on J.J. Hardy's grounder to short. But Johnson's throw was over first base and allowed Hardy to reach second. He scored on Guerrero's single to left.
"You could say that we shouldn't have pitched to (Guerrero)," Jays manager John Farrell said. "But in the end we were trying to pitch around him. The way Cecil was throwing the ball I had confidence that he'd retire him."
The Orioles scored again in the eighth when Markakis beat the throw to first on a double play attempt on his grounder to second. That allowed Ryan Adams, who led off the inning with a single, to score from third. His hit was followed by Andino's sacrifice and Hardy's single.
Cecil had his seventh strikeout of the game by his first batter in the fifth inning when Mark Reynolds struck out on a foul tip on a change-up.
"He had swing and miss type stuff tonight," Farrell said.
Guthrie, the major league leader in losses, has been a victim of poor run support this season. In his past 20 starts before Friday the Orioles scored a total of 68 runs when he was in the game, an average of 3.4. And in his first eight starts, the Orioles scored 10 runs while he was in the game, an average of 1.3.
So Guthrie took things into his own hands.
"You can't ever lose a game if you give up zero runs," Guthrie said.
The Orioles had not scored a run while Guthrie was in the game in six of his 28 starts before Friday. That includes three starts in a row from May 2-13.
"He was great, he was solid." Showalter said. "He really commanded the fastball and when it's there for him it presents a lot of issues. He and Matt (catcher Wieters) were on the same page, you could tell from the tempo. They presented a real confident front there. They had an idea of what they were going to do."
The Blue Jays threatened with two out in the seventh on Adam Lind's second hit of the game and a walk to Brett Lawrie of Langley, B.C. But Guthrie struck out Johnson.
The eighth also ended on a double play with Pedro Strop inducing the grounder from Eric Thames after a one-out error and a walk.
"The key double play there in the eighth inning on Strop was probably the one legitimate and true opportunity that we had to mount something," Farrell said. "But they snuffed it."
Jim Johnson, trying for his fourth save, walked Jose Bautista to lead off the ninth. But he got the next three batters on groundouts to end the game.
Notes: Attendance at Rogers Centre was 13,918 ....Lind was back in the lineup at first base after missing two games with a sore right wrist. .... Centre-fielder Colby Rasmus who is on the disabled list with a sore right wrist will start his rehabilitation assignment on Saturday with double-A New Hampshire. He will be used as designated hitter, play in centre field on Sunday and will rejoin the Blue Jays in Boston on Tuesday. ...Henderson Alvarez (1-2, 2.95 earned-run average) will start Saturday for Toronto against Rick VandenHurk (0-0, 2.45 ERA).