The visitors had led, 58-49, with 12:52 remaining.
"I saw them making a run, and I thought that me being a leader, it was for me to step up," said Guillandeaux, whose six three-point baskets were also a personal best. "It was surreal being back out there. All of that hard work paid off."
Columbia's Noruwa Agho, who poured in 21 points in the first 20 minutes to help give the Lions a 41-37 edge at intermission, finished with 26 points. In support of Guillandeaux, La Salle center Aaric Murray scored 19 points on 9-of-11 shooting from the field.
La Salle is coming off an injury-plagued season that ended with a 12-18 record under coach John Giannini, who is in his seventh season with the team.
Not counting Guillandeaux, La Salle had two new starters in Neumann-Goretti graduates Tyreek Duren and Earl Pettis.
Pettis, a 6-foot-5 junior, sat out last season after transferring from Rutgers. The 6-0 Duren gives La Salle a true point guard who looks to penetrate and dish. The freshman's first two baskets as a college player came on back-to-back steals in the backcourt. Both plays resulted in uncontested layups, and they gave La Salle a 12-7 lead in the early going.
But as the half progressed, Columbia began to take over behind Agho. Murray had 15 points at the break, and Duren had passed for six of his game-high nine assists.
"We hung together really nicely in the face of adversity, and that was huge," Giannini said. "It was a team-building win. This was a gut-it-out win. We persevered, and we're going to get better."
Contact staff writer Kevin Tatum at 215-854-2583 or ktatum@phillynews.com.
