As the game eased into injury time, Hoppers looked down and out trailing 34-21 and a losing bonus point seemed all that could be hoped for.
But the referee played nine minutes of injury time, and first Darren Wilson scampered 40 metres to score and Paul Bailey converted to achieve this feat.
Then in a frantic finish, Hoppers laid siege to the Lions' goal line and in the last play of the match the referee awarded a penalty try, Bailey again converted and Hoppers won by just one point.
Hoppers dominated the first 20 minutes but had only two Bailey penalties to show for it and the home pack began to assert themselves with a series of forward drives and rolling mauls which eventually led to lock Watson being driven over and Yuill's conversion gave his side the lead.
From here on Hoppers were chasing the game and some sloppy defence let in wing Collins for a converted try which put Leicester 17-6 to the good after 33 minutes.
Before halftime, Hoppers backs at last got it right and Olly Viney's timely incursion into the line put Owen McKenna in at the corner.
Although Bailey's kick failed, the visitors were at least back in touch as they went in at the break 11-17 down. Hoppers started the second period well and Dewhurst was driven over after just two minutes to bring them within a point but more poor defence let in Collins again and Yuill obliged to stretch the lead to 24-16.
Hoppers survived further pressure but on 68 minutes the backs found their touch again to send the prolific Viney in for his 11th try of the season.
Back within three points things were looking more promising for the visitors until home fly half Francis snaked through a host of Hoppers defenders seemingly rooted to the spot to touch down. Yuill's conversion and penalty on 79 minutes made the score 34-21.
But to their credit, Hoppers refused to give up and the win keeps them in third place.
On Saturday they travel to sixth placed Tynedale.
The final score was Leicester Lions 34 Preston Grasshoppers 35.
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