TORONTO -- The thrill of a walkoff win still hasn't gotten old for Justin Smoak, even after a decade in Major League Baseball.

Smoak drove in the winning run in the 11th inning as the Toronto Blue Jays completed a three-game sweep of the Oakland Athletics with a 5-4 victory on Sunday afternoon.

Toronto was trailing 4-1 entering the bottom of the inning but a three-run homer by Brandon Drury off A's closer Blake Treinen tied it up, and Smoak stroked a single to left field to bring home Freddy Galvis for the winning run.

"It's awesome any time you can get a walkoff," said Smoak. "Especially in the position we were in there and against one of the best closers in the game."

Eric Sogard was a triple short of the cycle for Toronto (14-14). Vladimir Guerrero Jr. went 1 for 4 in his third MLB start, drawing cheers with each at bat. He also reached base in the second inning on a fielding error.

"Honestly, I think over the past couple of weeks we've been better offensively," said Smoak. "I feel like we've been pitching well all year, so as long as we can keep scoring runs we've got a chance.

Trent Thornton gave up a run on two hits and five walks, but struck out seven in a five-inning no decision. It was an improved performance for the rookie who gave up a total of 13 runs over 12 2/3 innings in his past three starts, all losses.

"I just felt like I was being more aggressive with it today. I was trying to get ahead in the count," said Thornton. "It's probably the most walks I've ever had in my career, but I felt like I was being aggressive and going after hitters."

Daniel Hudson, Joe Biagini, Ryan Tepera, and Ken Giles each pitched an inning of scoreless relief. Thomas Pannone gave up three runs in 1 2/3 inning of work, with Elvis Luciano earning the first win of his career on just one out.

Kendrys Morales and Ramon Laureano drove in runs in the 11th for Oakland (14-16), while Khris Davis went 2 for 5 with an RBI double.

Chris Bassitt was dominant for seven innings, giving up three walks and one run with nine strikeouts but earned a no decision.

J.B. Wendelken and Joakim Soria each threw a scoreless inning of relief. Blake Treinen took the loss, giving up four earned runs in 1 2/3 innings of relief.

Morales, who was traded by Toronto to Oakland at the start of the season, singled to centre field in the top of the 11th, sending Stephen Piscotty to third. The A's right-fielder then scored on Laureano's deep flyball to centre field.

Billy McKinney misplayed Phegley's line drive off the left-field wall in the next at bat, bringing in Morales and making it 3-1.

After Pannone loaded the bases Luciano hit Chapman with a pitch to bring in another run.

Blue Jays first baseman Rowdy Tellez led off the bottom of the 11th with a ground-rule double and he advanced on McKinney's single to short. Drury's bomb to the second deck at Rogers Centre to tie it up 4-4 came next and set up Smoak's heroics.

It was Drury's second key home run in three nights, having hit the game-winning two-run homer in Friday's 4-2 victory over Oakland.

"I think baseball's a game of confidence and getting big hits and homers is going to give you confidence," said Drury after the first extra-innings homer of his career. "I was definitely excited about that walkoff (on Friday) and hopefully I can keep riding this wave here."

With Galvis on second and catcher Danny Jansen on first, Smoak stroked the ball to left field. The Blue Jays bench was already on the field celebrating before Galvis could reach home.

Sogard opened scoring in the bottom of the first off with a home run to right field. It's the second time in three games the Blue Jays shortstop has led a game off with a solo shot to right field. He did the same thing in Toronto's win on Friday.

Davis tied it 1-1 in the third inning, driving the ball to deep left field for a stand-up double and giving Chapman enough time to score from first.