It was a glimpse of what will await him when he gets home.
"That's what we play for -- them," Cain said after his franchise won its first World Series since 1954, when it played in New York. "To bring it back for them -- they've been waiting so long for this, and it's just been an incredible ride. They pour their hearts out for us every night."
Cain was the last Giants player to walk off the field and into the tunnel toward a frenzied visiting clubhouse that awaited him.
But he was the first one to step in with the World Series trophy raised high above his head.
Amid screams, tears and sheer joy, Cain handed off the hardware -- the first one of this kind that has ever belonged to San Francisco, even though the city has had a team since 1958 -- and it slowly made its way around, one "misfit" at a time.
It went to Buster Posey, the rookie phenom who exceeded even the lofty expectations he carried into this season.
It was then given to Cody Ross, the waiver pickup who wound up being the National League Championship Series MVP and a player the Giants simply couldn't do without.
It went to Aaron Rowand, who was on the White Sox team that broke an 88-year drought by winning it all in 2005.
On and on it went, making sure each of the players -- a lot of whom many said were too old, too young or simply not good enough to reach this stage -- saw what it looked like up close.
"Offensively, we just have a bunch of old guys," said Aubrey Huff, the lefty power hitter hardly anybody but the Giants wanted to sign this offseason. "These are just last-chance guys, second-chance guys, and you can tell it's a true team, man."
After a kiss from Barry Zito -- the $126 million starter who didn't have a place on this postseason roster -- it finally came around to Guillermo Mota, the 37-year-old reliever signed to a $750,000 contract. Mota took the prized possession, walked over to a nearby table -- Don't drop it, Mo!
his teammates hollered -- and he raised it up for everyone to see.
"We played as a team," scrappy second baseman Freddy Sanchez concluded. "We had that chemistry in the clubhouse. Off the field, everyone got along with everyone. We had so many diverse personalities, but everybody came together and wanted to win."
And so they did -- the way so many other great Giants teams never could.
Their 103-win club in 1962 -- with Willie Mays, Felipe Alou, Willie McCovey, Orlando Cepeda and Juan Marichal -- was defeated by a hard-to-sit-with score of 1-0 in Game 7 of the World Series by the Yankees.
The 1989 team composed of Will "The Thrill" Clark and Kevin Mitchell was swept by the hard-charging Athletics.
And despite holding a 3-2 lead in the Series and a 5-0 lead in the bottom of the seventh inning of Game 6, the Barry Bonds-led team of 2002 was taken down by the club that became that year's Cinderella team -- the Angels -- in seven.
Shawon Dunston hasn't forgotten. The Giants' current defensive coordinator, a utility player on that club, at one point stood in the corner of the clubhouse with the World Series trophy cradled in his arms. Pablo Sandoval tried to wrestle it away to take a picture, but Dunston wasn't having any of it.
"Let me hold it for my 2002 team!" Dunston said while pulling away and trying to drag Clark with him. "Just one more minute."
There was no Mays, McCovey or Bonds on this team -- maybe a Marichal or two -- but it didn't matter.
"We're champions anyway," Cain asserted.
Edgar Renteria, whose three-run homer was all the offense the Giants were able to muster against an otherwise-dominant Cliff Lee, was the last player to make his way into the celebration.
Known for his walk-off hit in Game 7 of the 1997 World Series, the 35-year-old shortstop went on the disabled list three times and temporarily lost his starting job in a year that may end up being his last.
But here he was in the World Series, batting .412 with -- wouldn't you know it -- two home runs to win MVP honors.
"Thankfully," Renteria said, "God gave me the opportunity to be in this situation and come through."
As the dry Renteria walked in, he was immediately assaulted by a mob of teammates, who doused him in champagne in celebration of his second stint as World Series hero.
"You see his face, he wanted to cry," Sandoval said. "But he's a tough man."
After a little more than an hour of celebration, the players decided to take the party outside. And, low and behold, there they were: The Giants fans, many of whom flew from San Francisco because they didn't want to miss history, hadn't moved an inch.
Sanchez was standing right in front, pumping them up with camera in hand.
"It's unbelievable, but this is San Francisco for you," he said with a smile. "The fans have been great."
A few hours before, the Giants had officially become champions, erasing the third-longest-running championship drought in the Majors. And in a few hours, they'd be heading home to take part in a parade and continue the celebration among family and friends.
As for when it would sink in?
"Probably when I get home and lay on the couch and realize, and watch footage from throughout the playoffs," Ross said. "Because right now this is a dream. I'm living a dream right now. I mean, I'm waiting for my wife to roll over and nudge me and say, 'Wake up.'
"This is ... I mean ... it's unbelievable."