SAN FRANCISCO -- The San Francisco Giants are struggling so badly for offense of late, they will take wins any way they can get them.

Buster Posey, mired in a 1-for-24 slump, didn't even have to swing the bat to knock in the winning run Wednesday. The catcher drew a bases-loaded walk in the 13th inning, giving the Giants a 5-4 win over the Toronto Blue Jays 5-4.

San Francisco avoided being swept in the three-game series.

"It was huge, especially having a lead like that, we coughed it up, that would've been a tough one to lose, getting swept and to hit the road on," Giants manager Bruce Bochy said. "But we kept fighting, and it wasn't pretty. A walk-off walk, it's big. You go to extra innings, you're fighting to keep from getting swept, and no question, a huge game for us."

In the other clubhouse, the Blue Jays skipper had a similar sentiment.

"You never want to lose a game on a walk, but that's over with,"

Toronto manager John Gibbons said. "The guys played a good game out there. We came back to tie it against a good pitching staff, we battled our (butts) off.

"We came up short, they've got a good team over there. I'm not going to sit here and nitpick on who didn't do what because you know what, they're busting their (butts). We'll leave it at that."

Brandon Belt was hit by a pitch leading off the 13th inning. Toronto failed to get an out on Denard Span's bunt, putting runners at first and second.

With Joe Panik at the plate, reliever Ryan Tepera uncorked a wild pitch, moving the runners to second and third. Panik was intentionally walked, loading the bases with no outs. With a drawn-in infield, Matt Duffy hit a soft liner to first baseman Edwin Encarnacion. That set it up for Posey.

"You get to the point where you're almost 4 1/2 hours in, does it matter?" Posey said. "I thought the guys that came in and pitched the 10th to the 13th did a great job facing a lineup that's got a lot of power up and down. We're able to scratch one out."

Toronto's Michael Saunders hit a solo homer to center in the ninth to tie the game 4-4 and force extra innings. He ended up with two hits in four at-bats after coming off the bench in the seventh inning.

"We're able to battle back, which is a good sign," Saunders said.

"Your whole goal is to try to win series, on the road especially. All season long, you try to win series. You win the first two and you try to get greedy, get the third one, but we battled hard, and it just didn't go our way today."

Giants starter Madison Bumgarner worked his way out of a bases-loaded jam in the first inning to toss 6 1/3 innings. He allowed only one run on three hits and four walks while notching five strikeouts in a no-decision.

Bumgarner showered praise on Albert Suarez, the last man standing in the Giants' bullpen, who picked up his first major league win.

Suarez (1-0) threw one scoreless inning despite yielding hits to the first three batters he faced. The leadoff man was out trying to stretch his hit into a double, and Suarez escaped a two-on, one-out jam.

"He was in a tough spot there, and the ball bounced his way," Bumgarner said of Suarez. "Anytime there's a first win, you're happy for him, especially a guy like that."

Toronto starter Marcus Stroman pitched six innings and allowed eight hits and four runs (two earned). He walked two and struck out five in a no-decision.

"It's just one of those days where balls are kind of finding holes,"

Stroman said. "I'm an aggressive pitcher. I stay in the zone, so for the most part, my guys are going to make those plays behind me and I have the confidence in them to do that each and every time."

Duffy went 3-for-6, and Hunter Pence and Brandon Crawford added two hits apiece for San Francisco. Toronto's Josh Donaldson went 4-for-6.

NOTES: Blue Jays LHP Aaron Loup (strained left elbow) threw 10 pitches in an extended spring training game Tuesday. It all is well, he will start a rehab assignment with high Class A Dunedin on Saturday. ... RHP Roberto Osuna, Toronto's 21-year-old closer, was not available Wednesday after pitching in three consecutive games. ... Giants RHP Sergio Romo was extended to about 35 pitches off the mound and continues making progress from a strained right flexor tendon. "There are no issues with his elbow," Giants manager Bruce Bochy said. "He's on his way." ... RHP George Kontos (right elbow flexor strain), currently on a rehab assignment, is expected to rejoin the Giants in San Diego next week. ... Giants C Buster Posey ended an 0-for-18 streak, the second longest drought of his career, with a first-inning single. He went hitless in 19 straight at-bats in July 2013.