One out away from ending a three-game losing streak, the Blue Jays let the victory slip away with a pair of botched plays in the bottom of the ninth.
Throwing errors by third baseman Brett Lawrie, his second miscue of the night, and catcher J.P. Arencibia, proved costly to Toronto in a 9-5, 10-inning loss to the Seattle Mariners on Friday night.
"Definitely gave one away," a downcast Lawrie said.
Michael Saunders hit two home runs, including a grand slam in the 10th as Seattle extended its winning streak to a season-high four games.
Manager John Farrell urged his team to use more caution and common sense with the game on the line.
"Errors are going to be made but when you can make a decision to prevent that, that's where we've got to be a little bit smarter," Farrell said.
Saunders started a two-run rally in the ninth with a shot to center, then hit the tiebreaking homer to right off Luis Perez (2-1) in the 10th, his first career slam and third homer of the season.
Charlie Furbush (2-1) got two outs for the win and Jesus Montero also homered for the Mariners, who had lost eight of their past nine games in Toronto.
Edwin Encarnacion and Eric Thames hit solo homers for the Blue Jays, who had won 13 straight extra inning games at home dating to 2010.
Trailing 5-3 to begin the ninth, the Mariners cut it to one when Saunders connected off Francisco Cordero. Clinging to the lead, Toronto was twice let down by its defense. Pinch-hitter Kyle Seager reached on a throwing error by Lawrie, with Adam Lind unable to make the scoop at first for the out that would have ended it.
"I take full responsibility," Lawrie said. "That game should be over. Everyone should be out celebrating a win, instead we're all a little bit down after that one, including myself."
Things got worse when pinch runner Munenori Kawasaki went to third on catcher Arencibia's errant pickoff throw that ended up in right field. Kawasaki scored the tying run on a single by pinch hitter John Jaso.
Farrell didn't think much of Arencibia's throw.
"I thought J.P. tried to force some things defensively," Farrell said.
Arencibia, meanwhile, wasn't questioning his decision.
"I don't play scared, I play aggressive," he said. "It's a high-risk play but I'd do it again."
The blown save, Toronto's fifth in nine chances this season, canceled a two-run Blue Jays rally in the eighth. Thames broke a 3-3 tie with a homer to center, his second. Lawrie singled and went to third on a throwing error by pitcher Tom Wilhelmsen before scoring on Arencibia's sacrifice fly.
Mariners starter Blake Beaven, who was on the losing end of Phil Humber's perfect game last week, saw Ricky Romero hold Seattle hitless through five innings in this one, although the visitors scraped out a run in the third thanks to a pair of walks and a fielding error by Lawrie.
The Blue Jays, who scored just three total runs during this week's three-game sweep in Baltimore, got their offense started when Encarnacion drilled a leadoff homer into the center field restaurant in the second. It was his fifth of the season.
Toronto took the lead with two in the fourth. Encarnacion hit a one-out double, Thames reached on an infield single and, after Lawrie popped up, Colby Rasmus drove in both runners with a double into the right field corner, putting Toronto up 3-1.
Romero lost his no-hit bid when Ackley led off the sixth with a double to right, and coughed up the lead in the seventh. Montero began the inning with a homer that scraped over the wall in left, his third. Romero got two outs but couldn't finish the inning, giving up a single to eighth hitter Miguel Olivo and an RBI double to ninth hitter Casper Wells. Romero was replaced after walking Ackley, with Jason Frasor coming on to retire Brendan Ryan.
Romero, who had won three straight starts coming in, allowed three runs and four hits in 6 2-3 innings. He walked three and struck out five.
Beavan gave up three runs and seven hits in 5 2-3 innings. He walked none and struck out four.
NOTES: Blue Jays OF Travis Snider, currently at Triple-A Las Vegas, underwent an MRI Friday after he jammed his right wrist while diving for a catch Thursday and was forced to leave the game. ... Toronto announced plans for peanut-free seating at three home games this season. Seats are reserved for people who suffer from peanut and nut allergies.