TORONTO - Rajai Davis is building a strong case to avoid being relegated to the Blue Jays bench.

Davis hit a tiebreaking double in the eighth inning and Toronto swept the Seattle Mariners with a 7-5 victory on Thursday.

It was the second time in three games Davis came off the bench to contribute in a late-inning win. He entered the game as a pinch-runner for Eric Thames in Toronto's three-run seventh inning.

"It just so happens that we're in a little bit of a stretch right where guys come off the bench and have contributed in a big way," manager Toronto John Farrell said. "Today was no different with (Mike) McCoy and obviously a huge hit by Rajai.

"He hasn't been relegated to a bench role but he has the knack for some flair late in the game. He's still going to get the majority of his reps in centre field."

The game was played with the roof closed at Rogers Centre because of sweltering conditions outside, with temperatures reaching the high 30s C.

It gave the Blue Jays a sweep of the three-game series and extended Seattle's losing streak to 12 games, prompting Mariners manager Eric Wedge to vent some frustration after the game.

"We've got to get tougher," he said. "This game will eat you up if you don't get tougher. They fought back today, but we've got to do a better job from inning to inning."

Mike McCoy, who played second base as Aaron Hill was given the day off, started the eighth-inning rally with a two-out double and Yunel Escobar walked to bring up Davis who got his big hit off reliever David Pauley (5-4).

In Tuesday's 6-5 win, Davis entered the game as a pinch-runner in the ninth inning and stole two bases in the 14th to set up the winning sacrifice fly by John McDonald.

Davis started both games on the bench because Travis Snider was used in centre field for both games to get more left-handed bats in the game.

Farrell even forgave Davis for thinking it was the ninth inning and that his hit was a walkoff double. Otherwise his speed might have given him a triple.

"I'm thankful he got the hit and yeah we do play nine innings," Farrell said.

"I guess I was just focusing on hitting and it felt good off the bat and I was admiring it a little bit," Davis said. "It was just a good pitch to hit and we were able to square it up and hit it where they ain't and we scored some runs."

Coming into games late is nothing new for Davis, although he has been mainly the starting centre fielder since joining Toronto this season in an off-season trade with the Oakland Athletics.

"I've had a lot of practice doing it," he said. "I did it a lot with Pittsburgh, I did it some with San Francisco, I did it a lot with Oakland and I think I got used to it and figured out a way to stay consistent."

It looked like a win for Blue Jays starter Ricky Romero who was looking for his first win since June 26.

But Mariners catcher Miguel Olivo hit a grand slam against Jays reliever Casey Janssen to erase a 5-1 lead after Romero left with one out in the eighth.

Romero struck out nine while giving up four runs and five hits in a no decision, his second to go with two losses over his past four starts.

Seattle starter Doug Fister, who could not get an out from five batters in the three-run seventh allowed five runs, four earned, five hits and three walks and did not figure in the decision.

Jon Rauch (4-3) took over from Janssen in the eighth and pitched the ninth to pick up the win.

In the fifth, Romero walked Chone Figgins and Jack Wilson with two out. Romero was walking off the mound thinking he had struck out Ichiro on a 1-2 pitch but the right-fielder had barely fouled it to stay alive. Ichiro then singled up the middle and the Mariners led 1-0.

The Blue Jays tied the game in the fifth on a double by McCoy that scored Edwin Encarnacion who led off with a walk and took second when J.P. Arencibia was hit by a pitch.

In the sixth the Blue Jays took a 2-1 lead when Jose Bautista lined a double to left to score Thames who reached first on a wild pitch after striking out. Thames turned his ankle slightly running the bases but is not expected to miss any time.

The Blue Jays loaded the bases in the seventh on Corey Patterson's infield single, Arencibia's walk and Fister's error on McCoy's bunt that loaded the bases. Yunel Escobar singled to centre to score a run, reaching base for a career-best 25 consecutive games.

Thames walked to force in another run and Chris Ray, who replaced Fister, gave up Bautista's sacrifice fly to increase Toronto's lead to four. Davis ran for Thames.

Ichiro and Ryan had one-out infield singles in the eighth. Olivo's slam, his 13th homer of the season, was the Mariners' first of the season.

"I'm not thinking home run at all," Olivo said. "I'm just trying to make contact to bring some runs in. And then he hangs the pitch and I made a good swing and I'm glad it happened. The team got up a little bit.

"I put a good swing on the ball and everybody thought we had a chance to win the game. But it did not happen again and you just need to keep trying."

Notes: Attendance at Rogers Centre was 23,146. ... Bautista made his third consecutive start at designated hitter on Thursday. He returned Tuesday after missing three games with an ankle injury. Manager John Farrell said Bautista likely will be back at third base Friday for the opener of a three-game series at Texas. ... Snider made his second start of the week in centre field after playing well there on Tuesday. It gave Toronto three left-handed bats in the outfield to face the right-handed Fister. ... Jo-Jo Reyes (5-7, 4.94) will pitch for Toronto on Friday against the Rangers Colby Lewis (9-7, 4.07).