TORONTO -- For a Blue Jays team that hasn't had much to smile about this season, this was the laugher they've long been waiting for.
"We were desperate for that. We needed something like that," manager John Gibbons said. "It's not like we're just waiting to get on a roll. We needed a win and they're hard to come by."
Brandon Morrow pitched three-hit ball over eight innings for his first win of the year. He struck out eight, matching a season high.
"Definitely a morale booster," Morrow said.
Cabrera was 3 for 4 with two RBIs while DeRosa went 3 for 5 with three RBIs and scored three times as the Blue Jays improved to 8-0 when scoring five or more runs. Toronto's 10 runs matched a season high.
"That's a pretty good recipe today for winning," Gibbons said. "Great pitching and we made a lot of things happen offensively."
The last-place Blue Jays had lost 14 of their previous 18, a disappointing stretch for a team expected to contend in the AL East this season.
"It wears on you a little bit," Morrow said. "Guys would come in every day ready to play and in the right state of mind, but there's some things throughout the games, maybe not even things in our control, just little things here and there that you say things are just kind of against us right now. That starts to wear on you, but today was a good day for us."
DeRosa, who called a team meeting before last Sunday's loss at New York, one that capped a four-game sweep by the Yankees, insisted the Blue Jays remain confident in their playoff chances despite being 10 games under .500.
"No one has given up in here," De Rosa said. "We're going to keep fighting and we've got the guys to do it."
Morrow (1-2) allowed two runs and walked a season-high five in the longest outing by a Toronto starter this year. He had not won since beating Minnesota last Oct. 3, the final day of the 2012 season.
"We definitely needed that," Gibbons said of Morrow's long outing. "Our bullpen is beat up."
Steve Delabar finished in the ninth for the Blue Jays, who outhit Seattle 15-3 and improved to 7-12 at home.
Mariners left-hander Joe Saunders (2-4) allowed seven runs and nine hits in five innings, losing for the third time in four starts. Saunders walked two, struck out none and dropped to 0-4 with a 12.53 ERA in four road starts.
"I just think it's somewhat of a fluke thing right now," Seattle manager Eric Wedge said. "It's gained a little bit of momentum and we've got to stop it."
The Blue Jays opened the scoring in the first when Rajai Davis doubled, advanced on Cabrera's sacrifice and scored on Jose Bautista's sacrifice fly to shallow right field, a high popup that was caught by second baseman Dustin Ackley after he struggled with the sun.
Morrow retired 10 in a row before running into trouble in the fifth, when he gave up two runs on four walks and a single. Robert Andino drove in the first run with a fielder's choice and Kyle Seager added a sacrifice fly.
"I just got a little too loose in my mechanics, but I cleaned it up and was good the rest of the time," Morrow said.
The Blue Jays pulled away with a pair of homers in the bottom half. Cabrera led off with his first of the year, a drive off the facing of the second deck in left, and mimed high-fives after his teammates jokingly failed to respond upon his return to the dugout.
Toronto made it 8-2 with a run off Hector Noesi in the sixth, with Kawasaki scoring on Encarnacion's bases-loaded fielder's choice. The Blue Jays added two more in the seventh on RBI singles by Kawasaki and Cabrera.
Morrow, meanwhile, responded to his shaky fifth by retiring eight straight -- four on strikeouts. The streak ended when Kendrys Morales doubled on an infield popup in the eighth after first baseman Encarnacion tripped over the mound.
"I feel bad because it's probably my ball," said DeRosa, the third baseman. "It was a high sky. I kind of went for it and was waiting for someone to call it. He called it and the next thing I know he's on the ground. When you win the game 10-2, you can laugh those things off."
The Mariners have not swept a three-game series in Toronto since May 11-13, 2001. ... Seattle OF Michael Saunders made a leaping catch at the wall to take extra bases away from Arencibia for the final out of the third. ... Blue Jays 3B Brett Lawrie got the day off. ... Toronto RHP Justin Germano, designated for assignment last week, has been sent outright to Triple-A Buffalo. ... The Blue Jays play 10 of their next 12 games on the road.