It was hard to tell who was more surprised on Sunday afternoon at Detroit, the guy with the game-winning home run or the pitcher who gave it up.

Lyle Overbay took normally overpowering stopper Jose Valverde into the left-field stands for a two-run dinger that led the Toronto Blue Jays to a 5-3 victory over the host Tigers that deepened the gloom in the Motor City.

Detroit (50-46) has now lost nine of its last 11 and has a chance to make it 10 of 12 as the second game of this day-night double header is scheduled for 6 p.m. ET.

Toronto improved to 50-48 with its second-straight victory.

Valverde, who had given up just one run in his last 21 appearances, came in to pitch the ninth inning of a 3-3 tie, just minutes after the Tigers had evened things with one run in the eighth.

Vernon Wells promptly lined one off the pitcher's calf for an infield hit. Out came the trainer to check, but the big right hander seemed all right.

He struck out two in a row before Overbay came up and launched an 0-1 split-finger fastball out for his 11th homer of the season. That was just the second round-tripper Valverde had allowed in 2010, the last one coming on April 11.

Gregg gets the save

Toronto closer Kevin Gregg, who had blown a game in Kansas City earlier in the week, picked up his second save (now 23 overall) in two days as he cruised through the ninth.

He ended the game by getting Austin Jackson to fly out to right. Jackson had come to the plate needing just a homer for the cycle, having singled, doubled and tripled earlier.

Brett Cecil left after seven strong innings of two-run, six-hit ball, striking out a half-dozen and walking just one, that intentionally.

In came Shawn Camp to hold a 3-2 lead.

His last appearance on Thursday night in the first game of the series had also come in the eighth inning where he allowed the winning runs in a 5-2 defeat.

This time, Camp gave up a lead-off triple by Jackson, walked Ramon Santiago, got Ryan Raburn to pop out to the catcher and then allowed a Texas Leaguer to centre by Miguel Cabrera that fell in front of Wells to tie the game.

Out went Camp and in came lefty Scott Downs who, after a walk, struck out the next two guys to get out of the mess. He would get the win (4-5).

Detroit starter Armando Galarraga lasted seven innings on three earned runs off five hits and five strike outs. He walked none.

Robbie Weinhardt pitched the eighth and handed off to Valverde.

Good defence early

Catcher Jose Molina put the Jays up 2-0 in a strange sixth inning at-bat that began with the embarrassment of a failed sacrifice bunt attempt and ended with the ball in the hands of a fan over the left-field wall.

The blast, his third of the season, also scored Edwin Encarnacion.

Cecil threw the lead right back, giving up a home run to ninth hitter Danny Worth and then a two-out double by Raburn that brought home Jackson's two-base hit for 2-2.

Over to Galarraga, who opened the top of the seventh by serving up a hanging slider that Wells whacked over the wall in left for his 15th homer of the year, making it 3-2.