TORONTO -- Rowdy Tellez was pleased to get a good result against a tough left-handed reliever at the major league level on Tuesday.

But even hitting a grand slam -- the first of Tellez's career -- lost its lustre when it came in a losing effort.

Tellez sent a pitch from Tony Watson deep into the centre-field seats in the eighth inning to bring Toronto within a run, but the San Francisco Giants held on to beat the Blue Jays 7-6 in the opener of a two-game interleague series.

"We lost tonight so it's a tough one for me, kind of a meaningless home run in the scoreboard," the Blue Jays rookie said. "But mentally, it's nice to have a good at-bat against a tough lefty out of the bullpen."

Joe Panik homered and drove in three runs, Kevin Pillar had an RBI in his return to Rogers Centre, as the Giants handed Toronto its first loss in five games.

Pablo Sandoval, Brandon Belt and Evan Longoria also hit home runs as San Francisco (10-14) build a 7-2 lead.

Tellez's eighth-inning grand slam gave the Blue Jays (11-13), and their rookie manager Charlie Montoyo, some hope before Will Smith shut down Toronto in the ninth to pick up his sixth save.

"You know what I like about this team? We don't quit," said Montoyo. "You never see me smile after a loss but man this is pretty cool. That's what I was thinking on the bench."

Montoyo opted to keep Tellez in the game after the Giants brought in Watson despite the lefty-lefty matchup.

"He's got a chance to hit a grand slam any time he goes to the plate with the bases loaded, I know that," Montoyo said of the decision. "That's why we kept him against the lefty. He's got power, he's got a chance to hit the ball out."

Eric Sogard extended his hit streak to six games with a solo homer and Socrates Brito had an RBI triple.

Tuesday marked Pillar's first game in Toronto since the centre-fielder was traded to the Giants on April 2. Pillar had played seven seasons as a Blue Jay and was selected by the team in the 32nd round of the 2011 draft.

The Jays honoured Pillar with a video tribute in the first inning, which he watched from the field while receiving a standing ovation. The 30-year-old tipped his cap to fans when it was over.

He also received loud applause from the crowd of 20,384 before his first at-bat in the second inning, which resulted in an RBI single to bring in San Francisco's first run.

"I'm a pretty emotional guy, so I held back some tears there and tried to focus on the things I needed to do and in some way I think that helped me in my first at-bat," Pillar said of the video tribute.

Jeff Samardzija (2-1) allowed two runs and five hits with a walk and four strikeouts over 5 1/3 innings. Rookie right-hander Trent Thornton (0-3) allowed four runs with six hits and five strikeouts over five innings.

Panik gave the Giants a 4-1 lead in the fifth inning with a solo blast. It was the first home run of the season for the nine-hole hitter, who came into the game with a measly .177 batting average.

Panik earned his first two RBIs of the game on a two-run double in the second that followed Pillar's run-scoring single. The Giants jumped on Thornton with four straight two-out hits in the frame en route to a 3-0 lead.

Brito tripled in a run -- just his second hit in his first 25 at-bats as a Blue Jay -- to put Toronto on the board in the second.

Longoria hit a solo homer off reliever Thomas Pannone in the sixth to make it 5-1, but Sogard replied in the bottom of the frame with his own solo shot. The infielder came into Tuesday batting .409 in his first five games since being recalled from triple-A Buffalo last week.

Belt's eighth-inning homer, also off Pannone, restored San Francisco's four-goal cushion and Sandoval followed with a solo bomb off Daniel Hudson for a 7-2 lead.

NOTES: The teams close out the two-game series Wednesday afternoon. Right-hander Clay Buchholz will start for Toronto while the Giants counter with lefty Drew Pomeranz. ... The Blue Jays announced before the game that No. 2 prospect Bo Bichette sustained a broken left hand when he was hit by a pitch on Monday night. ... Toronto's Freddy Galvis made a pinch-hit appearance in the ninth, extending his iron-man streak to 349 games.