While the players say they have a great support system at Loyola's Charles Street campus - everyone from the coaching staff to professors to the administration to staff psychologists - they get the most help from Geppi-Aikens.
"She gives them permission to ask questions and to express some of their emotions that may be difficult to express otherwise," said Dr. Jason Parcover, a Loyola counseling center psychologist who works with the team.
"Not only is she allowing them, and helping them, to do what they need to do to take care of themselves as a team, but she's also helping them to maintain focus on academics and on doing what they need to do on the field. And she continues to challenge them to succeed in ways they've become accustomed to over the years."
On the field, the Greyhounds' ability to stay in the moment - one of many life lessons learned from Geppi-Aikens - keeps them running on an even keel, goal to goal and game to game.
"It's hard, but you do what you think she would want you to do," freshman goalie Cindy Nicolaus said. "Diane doesn't want us to be upset for her or sad. She doesn't want sympathy. She wants us to do our best and succeed."
So the Greyhounds go about their business as they always have for Geppi-Aikens, playing hard, but drawing extra resolve from her presence when they need it.
Rachel Shuck, the junior playmaker who assisted Talia Shacklock's game-winning goal, said one glance to the sideline provided all the incentive necessary to upset the nation's No. 1 team on its home field.
"I know it's hard for Diane sitting in that wheelchair, but she's still so intense, so excited about everything," Shuck said. "She had us all give each other a hug right before the overtime. Things like that make you say, 'I want to win this for her.' She wants it so bad."
Every time the Tigers appeared ready to take control - building a three-goal lead early and tying the game with seconds to go in regulation and again in the first overtime - the Greyhounds found an answer.
"It was evident in that game that they had a little extra something," said Princeton coach Chris Sailer. "I remember walking off there feeling Diane definitely was the 13th person on the field and that team has something special about them, that they want to try to make such a great season for themselves and for Diane."
Although Geppi-Aikens has relinquished most of her responsiblities to Johnson, a former Loyola All-America midfielder, the transition appears seamless.
Geppi-Aikens doesn't make it to many practices, but she's still the coach at games, providing inspiration and instruction to both players and coaches. Everyone gets advice, high-fives and hugs.
"This isn't just about being No. 1 and winning. This is about having fun, and this team is having fun. We hug a lot. We kiss a lot," Geppi-Aikens said.
"We do play with a lot of emotion, but I don't know necessarily that that's tumor-based. Hopefully, I would have come with the intensity and the emotion anyway."
Geppi-Aikens will be putting it all out there as long as she can. And the Greyhounds will keep soaking up the lacrosse lessons and the life lessons she imparts.
"Diane always tells us, 'Have no regrets,' " Schuerholz said. "That's really important. That's the way she's always lived her life. As long as we play our best and do the best we can on that given day - as long as we don't have any regrets - I think it'll be all right."