Gersbach started at left back for his Ligue 2 side Lens and played all 120 minutes as the match remained deadlocked at 0-0 after extra time.
With the game destined to be decided from the spot, the 20-year-old former Sydney FC defender cooly slotted his side's second penalty kick with a well hit strike to the bottom left corner.
However, it wasn't to be for Gersbach and Lens with their third and fourth spot kick saved by Le Herbiers goalkeeper Matthieu Pichot to give his third-tier side a fairytale berth in the semi-final of the French Cup.
Gersbach may have had composure at the penalty spot but it was missing for fellow fringe Socceroo Mustafa Amini.
24-year-old Amini failed to convert from the spot while playing for club side AGF Aarhus against AC Horsens in Denmark's Superliga after his side won a penalty five minutes into the contest.
Fortunately for the Australian midfielder, his team opened the scoring only seconds later to take a 1-0 lead to the half time interval.
Amini, formerly with Central Coast Mariners and Borussia Dortmund, and his side looked set to collect three points but Horsens snatched a draw at the death with a 94th-minute strike.
It was a bittersweet result for Amini who played 83 minutes before being substituted.
In England, Jackson Irvine's Hull City kept their Championship survival hopes alive after earning a vital point in a 1-1 draw with Barnsley.
Barnsley took the lead after 22 minutes but Hull struck back midway through the second stanza courtesy of defender Michael Dawson.
Irvine played all 90 minutes of the contest in a holding midfield role.
Hull City sit three points outside relegation in 20th position after 33 games.
They play their next match on Sunday (AEDT) when they travel to Ipswich Town.