Geib's team-high ninth goal of the season tied the score at one at the 76:27 mark. The Green Knights had netted the game's initial goal just 37 seconds earlier.
Both teams attempted three shots in a scoreless opening half and the home team had a 10-7 advantage in that category in the next 45 minutes. St. Norbert also had a pair of shots attempts in the first 10-minute overtime period before scoring the game-winner with less than 20 seconds to play in the second.
Forester senior goalkeeper Tero Elias made three saves in the contest.
The loss dropped Lake Forest's overall record on the season to 6-5-1 and evened the team's Midwest Conference mark at 2-2-0. St. Norbert improved to 10-0-1 overall and 4-0-0 in the league.
The Foresters will host a pair of conference games next weekend, welcoming Monmouth College to campus for an 11:00 a.m. contest on Saturday before taking on Knox College at the same time on Sunday. Saturday's contest will be played on the soccer/softball field behind the Alumni Memorial Fieldhouse and Sunday's on Farwell Field, the team's regular home.