TORONTO (AP) -- Oakland manager Bob Geren knows what really beat the Athletics: sloppy defense.
Yunel Escobar hit a game-ending two-run homer in the 10th inning, lifting the Toronto Blue Jays to a 7-6 victory over the Athletics on Tuesday night.
Oakland made two errors and misplayed another potential out in a pivotal four-run sixth as the Blue Jays erased a 5-1 deficit.
"We had a rough inning there," Geren said. "Definitely, the errors cost us. You look at a walkoff homer as how you lost but it was the four-run inning where we didn't catch the ball that really killed us."
Josh Willingham hit a leadoff homer in the top the 10th to give Oakland a 6-5 lead. But former Oakland outfielder Rajai Davis led off the bottom half with a single against Grant Balfour (0-1) and Escobar followed with a first-pitch homer that landed in the right field bullpen, his first of the season.
"It couldn't have worked out any better for them," Balfour said. "A hit and a bomb and they're walking off like that. It's definitely not the way I saw it going out there. I felt good. I'm just annoyed at myself for not executing a couple of pitches there."
Geren went to Balfour because left-hander Brian Fuentes is sidelined with a blister on the middle finger of his pitching hand, something that's bothering him for the past few days.
"We're hoping that he'll be ready (Wednesday)," Geren said of Fuentes. "Today was the first time he could play catch in a couple of days."
Escobar sensed he would deliver the big hit.
"When we started getting closer, I got the feeling that I was going to win this game," he said through a translator.
Blue Jays right-hander Jason Frasor (1-0) earned the win despite allowing Willingham's homer.
The Athletics were punished for two errors. Oakland, which committed seven errors over the weekend in losing two of three at home to Seattle, leads the majors with nine miscues. The A's made 10 errors in their first four games of the 1970 season, a club record.
"We were a good defensive team last year and I fully anticipate us being a good one this year, too," Geren said.
Oakland opened the scoring with a three-run, five-hit third against Blue Jays left-hander Jo-Jo Reyes. Conor Jackson and Mark Ellis each hit RBI doubles and David DeJesus drove in a run with an infield single.
The Athletics chased Reyes with two more in the fourth. Andy LaRoche singled home a run and Willingham hit a sacrifice fly off reliever Carlos Villanueva .
Toronto got one back in the bottom half off Oakland starter Brandon McCarthy , who didn't give up a hit to the first 10 batters he faced. Escobar ended that streak with a single, went to third when Adam Lind singled off the first base bag and scored on Aaron Hill 's fielder's choice.
The Blue Jays took advantage of sloppy Oakland defense to tie it in the sixth. Davis led off with a double and Escobar singled off the glove of third baseman Kevin Kouzmanoff before Lind hit a sacrifice fly. Hill hit an RBI single and took second on McCarthy's throwing error before Juan Rivera reached on a throwing error by Kouzmanoff. Edwin Encarnacion made Oakland pay with an RBI double and Travis Snider capped the rally with an RBI groundout.
Escobar's single was originally ruled an error but was changed to a hit after the game. Either way, Kouzmanoff was left frustrated.
"Those plays have to be made," Kouzmanoff said. "Those are routine plays and I didn't get my job done at third base tonight."
Limited to 22 starts over the past three seasons because of shoulder problems, McCarthy made his first start since Oct. 2009. He allowed five runs, four earned, and seven hits in eighth innings, walked one and struck out two.
"It felt the way I remembered," McCarthy said. "It's fun to be back in a big league ballpark and competing in a big league game."
Reyes allowed five runs and nine hits in 3 1-3 innings, walking one and striking out three.
Coco Crisp hit a one-out double off Jon Rauch in the top of the ninth but Davis ended the inning with a running catch on the warning track to retire Jackson.
NOTES: Seven of Oakland's 13 hits were for extra bases, including six doubles. ... Blue Jays OF Jose Bautista left the team Tuesday for the birth of his first child, a daughter. He's expected to miss the entire three-game series against Oakland, returning Friday when Toronto visits the Los Angeles Angels . ... Davis returned to the lineup after missing two games with a sore right ankle. ... Attendance was 11,077.