Cambridge's hopes of securing promotion to Sky Bet League One on Friday night were wrecked in an extraordinary nine-goal thriller at Harrogate.
Centre-back Kevin Lokko, who had not featured for Town since being sent off against Blackpool in November, secured a 5-4 triumph in the 84th minute.
It was a second-string home team as boss Simon Weaver made eight changes to his starting line-up, with Monday's rescheduled 2020 FA Trophy final against Concord Rangers at Wembley in mind.
Brendan Kiernan, who had only previously managed one league goal all season, had earlier completed his hat-trick with only 32 minutes on the clock as Harrogate led 4-2 at the break.
U's striker Paul Mullin replied with a second-half brace to take his season's tally to 33, only for Lokko to prove the unlikely party pooper.
Barring the unlikeliest of goal-difference swings, a point in Yorkshire would have been sufficient to secure promotion for Mark Bonner's men.
Harrogate took the lead in the ninth minute when Kiernan converted right-back Ryan Fallowfield's low cross.
Mark Beck was then next to profit from an overlapping surge from Fallowfield, with his carbon-copy centre tapped in by the former Carlisle striker.
Cambridge continued to be tormented by Kiernan, who latched on to Greg Taylor's woeful headed backpass before being knocked off balance as he rounded away keeper Callum Burton.
He drove the resulting penalty straight down the middle of the goal as Burton dived to his left, before Cambridge hit back with two goals in the space of three minutes.
First, Wes Hoolahan fired in from just inside the penalty area after a ball into the box had been won in the air by Joe Ironside, who then provided the pass for Luke Hannant to net from eight yards out.
But Kiernan went on to claim the match ball after he prodded in when Burton spilled a low George Thomson strike.
After the interval, Mullin converted a Hoolahan cross just before the hour mark and, after the latter was hacked down by Jay Williams, levelled from the penalty spot.
Lokko, however, had the final say when he drilled in through a crowded penalty box.