The Americans are pursuing an unprecedented third consecutive title with Sullivan among 14 World Cup first-timers, nearly twice as many as in the U.S. team that competed in 2015.
But veteran defender O'Hara believes experience on the World Cup stage does not necessarily translate to impact on the field and pointed to Sullivan, who was sharing the stage with her at a news conference on Tuesday, as a prime example.
"Andy is bringing something very different than I was bringing as a player in my first World Cup," said O'Hara, who is competing in her fourth.
"To me, she's going to be so impactful on the field and is going to, you know, just change games for this team and it doesn't matter if it's her first or fourth. Like that's just the player that she is."
For Sullivan, the appeal of having O'Hara in the squad is obvious: "The veterans have been so incredible at telling us what we're getting into."
O'Hara is one of five holdovers from the winning 2015 and 2019 squads, including Alex Morgan, Alyssa Naeher, Julie Ertz and Megan Rapinoe.
Rapinoe, who won the Ballon d'Or in 2019, announced recently that this would be her last World Cup.
The roster spans some two decades, with 38-year-old Rapinoe the oldest and recently minted high school graduate Alyssa Thompson the youngest at 18.
"All the veterans, they want to perform their best, but they're also still looking out for us newbies," said Sullivan, who earned her first cap in 2016.
"It gives the whole team a sense of confidence ... it's interesting for me, because this is like a once in a lifetime opportunity. But then there's someone sitting next to me who's done it how many times."
