TORONTO -- Chris Waters pitched eight shutout innings in his major league debut last month. On Tuesday night, the left-hander went one better.
In his Aug. 5 debut, Waters allowed one hit in eight innings in a 3-0 road victory over the Los Angeles Angels.
"Both of them are a dream come true," Waters said. "For my debut to be as good as it was, and then for me to be able to complete the game today with a shutout, that's special. It doesn't matter if it's the first one or the 300th one."
Orioles manager Dave Trembley praised Waters for getting ahead and working quickly.
"He had very good tempo," Trembley said. "He looked like he was in complete control from the first pitch of the game to the end."
Baltimore, which had lost 17 of 21 coming in, posted its first shutout since beating Texas 9-0 on Aug. 9.
Toronto lost its third straight and saw a six-game home winning streak ended. The Blue Jays had won seven of their past eight games against the Orioles.
Making his ninth major league start, Waters (3-3) walked two and struck out three. The left-hander was 0-3 with a 6.45 ERA in his past four outings.
"Anytime I'm out there I want to go all nine," Waters said. "Sometimes you don't have what you need to do it but tonight was special."
"I thought he had a great game plan," Trembley said. "He didn't give in, didn't try to do too much, didn't change his approach. He stuck with it and he threw strikes. He got ahead and didn't try too overthrow. When they fouled pitches off, he kept coming right at them. He deserved an opportunity to finish the game. I'm real happy for him and so is the team."
Scott opened the fourth with a drive to straightaway center, his 23rd, off reliever John Parrish, as the Orioles won consecutive games for the first time since a three-game winning streak from Aug. 13-15.
"That was the real deal," Trembley said of Scott's homer. "He didn't miss it."
The Orioles had chances for more runs, but Ramon Hernandez grounded into a double play with the bases loaded to end the third and Brian Roberts stranded two runners with an inning-ending double play in the fourth.
Toronto starter Shaun Marcum (9-7) left after two-plus innings because of tightness in his right forearm that led to numbness in his pinky. Marcum missed 27 games earlier this season with a sore right elbow.
The right-hander gave up a double and a walk in the first without allowing a run and set the Orioles down in order in the second before running into trouble with his control in the third.
No. 9 hitter Juan Castro walked and scored on a double by Roberts before Marcum walked Nick Markakis, bringing manager Cito Gaston and trainer George Poulis to the mound. After a brief discussion, Gaston called Parrish out of the bullpen as Marcum and Poulis headed to the dugout.
"We'll see what the doctor says," Gaston said of Marcum. "If they recommend we shut him down we probably will."
Baltimore third baseman Melvin Mora threw his bat onto the field after he was ejected by home plate umpire Rob Drake in the third. Upset after being caught looking at a knee-high fastball, Mora argued with Drake and was ejected as Trembley ran out to try and break it up. With Aubrey Huff batting, Mora tossed his bat into foul territory as he left the dugout.
Already upset, Mora got even angrier when he thought Drake called him stupid, but Drake said that wasn't how the conversation went.
"After he got ejected, I said 'That was stupid,' meaning that was stupid for you to get ejected over this situation," Drake said. "And he goes 'What was stupid?' And I said 'That was stupid."
Mora wasn't sure whether he would be suspended for throwing the bat.
"That was my reaction," Mora said. "If I did something wrong, I apologize for that. The players get suspended but my question is, who suspends the umpire?"
It was Mora's first ejection of the season and the 12th for the Orioles.
Orioles RHP Dennis Sarfate, who has been pitching with an injured clavicle since April, underwent a CT scan and is deciding whether to have surgery. ... Toronto C Rod Barajas (hamstring) missed his third straight game. ... Blue Jays LHP Scott Downs, who aggravated his sore ankle Saturday, was not available Tuesday and may have to be shut down for the season. ... LHP Erik Bedard was the last Baltimore pitcher to throw a complete-game shutout, beating Texas on July 7, 2007.