It wasn't even the Blue Jays' power duo of John Buck, who hit two home runs, and Aaron Hill, who tallied three doubles and three RBIs.
It was the seventh pitch of an at-bat by Blue Jays starting pitcher Shaun Marcum with two outs in the second inning, where San Diego starter Jon Garland clearly thought he hit the outside corner of the plate for strike three.
Not according to plate umpire Larry Vanover. He called it ball three.
"I was out of that inning on a pitch [Vanover] had already given me, and then he didn't it to me," Garland said.
Two pitches later, Garland walked Marcum to keep the inning alive for the top of the order.
That's when Garland admitted he lost his composure.
Back-to-back doubles by DeWayne Wise and Aaron Hill followed the free pass to the opposing pitcher, which gave Toronto (35-30) the 4-0 cushion that would hold up for the rest of the ballgame.
"I mentally lost it," Garland said. "I was frustrated and upset, because I felt I did what I needed to do. It almost seemed like [Vanover] kind of let me down. ... I still had an opportunity to get out of that inning, and I didn't. I'm definitely going to go home and be very [upset] at myself. I am [already]."
Other than that four-run spurt, Garland, who was pitching on three days' rest because of a rainout doubleheader in New York last week, held the Toronto bats in check for five innings. He allowed six hits, struck out seven batters and walked four.
"I felt really good, actually," Garland said. "[I had] command of all my pitches. I was keeping them down in the zone, throwing them well [and] throwing them up in the zone when I wanted to. It honestly didn't even feel like there was short rest there."
But that one pitch to Marcum out of the 114 he threw, and the call that followed, still lingered in his mind.
"I said some things [to Vanover] that any given day gets you run out of a game, and he wouldn't even look at me, which tells me he knows he was wrong," Garland said. "At least be a man and admit it to me. If you feel you're wrong, just admit it to me."
The Padres (37-27) got two runs on leadoff homers by Jerry Hairston Jr. in the third inning and Adrian Gonzalez in the fourth, but San Diego's biggest missed opportunity to do damage against Marcum (6-3) came in the seventh inning.
After Scott Hairston reached on a single, Yorvit Torrealba also got on base when Blue Jays shortstop Alex Gonzalez booted a potential double-play ball. Will Venable then lifted a soft single into center field, and the Padres had the bags full with no outs.
But Marcum retired Jerry Hairston Jr. on a flyout to shallow left field on the first pitch, and Tony Gwynn grounded out to bring in a run to make it 5-3. Finally, Marcum, with runners on second and third base, got pinch-hitter Oscar Salazar out on his front foot on an 81-mph changeup, as he lifted a harmless fly ball to left field to end the inning.
"That was our chance," Padres manager Bud Black said. "Bases loaded, no out and we only got one in. A big hit anywhere in there would prove to be a different ballgame. I think [Jerry Hairston] had a good swing, [but he] just got underneath it."
According to Garland (6-5), it should have been a different ballgame from the second inning on. He said what he thought was a blown call behind the plate changed the entire complexion of the contest.
"As players, all we can ask is [for the umpires] to be consistent," Garland said. "When you give me a pitch on the outside, I'm going to continue to hit that spot, because you've already told me, 'Yes, Jon, I will give you that,' so why am I not to believe I'm going to get that all night?
"[Vanover] was bad tonight. He was really bad tonight. I feel it cost me two runs, I feel it cost me this game. Mentally, as a team, when you're down, 2-0, [it's a] completely different ballgame than when you're down, 4-0."