Holy Cross had led 21-0 but was forced to overcome a spectacular performance by Lehigh's Matt McGowan who had 21 carries for 179 yards.
Holy Cross (4-3, 2-0 Patriots League) had taken a 21-0 lead early in the second quarter, led by the passing of Randolph, who completed 28 of 39 attempts for 330 yards. The team also was bolstered by the running of Mike Kielt, who had 18 carries for 108 yards.
Randolph completed a 4-yard scoring pass to Brock. Drew Volkman scored on a 1-yard plunge and then Kielt broke through the line for a 37 yard scoring run.
McGowan, however, rallied Lehigh (2-5, 1-1). He scored two touchdowns after Alex Wojdowski caught a five-yard scoring pass from quarterback J.B. Clark (15-35-166) -- including a 46 yard pass and a 66 yard run to tie it, 21-21 with 13:25 left.
The Crusaders' Randolph, however, was not done. He directed an 11-play-71 yard scoring drive, finding Brock for a 2-yard scoring pass to win it. The outcome marked the first time Holy Cross defeated Lehigh on its home field since 1992, after eight straight losses.