While Upton assumed center-field duties for the franchise's first World Series game, younger brother and Arizona outfielder Justin Upton looked on from his seat inside Tropicana Field.
"I'm proud of him," Justin Upton said. "And I played against guys like [Evan] Longoria in the Minor Leagues, so it's fun to watch. I'm happy to see these guys here."
No one is happier than big brother B.J., who spent last season with the dead-last Rays and got his only whiff of the postseason watching Justin Upton's D-backs play in the National League Championship Series at Chase Field.
"I was on the other side of things last year, watching him in the playoffs," said B.J. Upton, who witnessed Justin's playoff debut just two months after his initial big league callup.
But Wednesday night, the tables were turned, and the spotlight was on the 24-year-old Rays outfielder instead.
"I think it should be a lot of fun," B.J. Upton said. "Anytime you know your friends and family get to come and watch this, it's a cool thing."
And perhaps now that both Uptons have played in the postseason, the sibling rivalry will be more of the good-natured kind.
"I didn't rag on him too bad last year when he had to come watch me play," Justin Upton said. "So he hasn't been messing with me too much."
Still, the elder Upton has seven home runs this postseason, tied with the Angels' Troy Glaus (2002) for most by any American League player. His 11 RBIs in the ALCS against Boston tied the record for most in a single postseason series, and his total of 15 postseason RBIs is just four shy of the Major League record.
He hasn't gloated any to his baby brother?
"He hasn't done any of that yet," Justin Upton said. "He will, though. There will come a point where we will be joking on each other and it will come up."
But the 21-year-old will take any ribbing in stride.
"He struggled a little bit during the season with injuries and things, and for him to be able to come out is exciting," Upton said. "And for [the Rays] to get as far as they have with Longoria and him and the pitching, it's fun to watch."
Although Wednesday's contest wasn't particularly fun for B.J. Upton -- who went 0-for-4 -- Justin Upton was definitely enjoying being a spectator at the World Series -- so long as it's not a yearly tradition.
"I'm excited for [B.J.], and [Arizona's] goal as a team also is to get there," he said. "So hopefully we will get back there next year and play these guys.
"But for him to make the World Series this year and to be a part of the only thing going on, the biggest game in baseball, you can't ask for much more."
Brittany Ghiroli is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.