Cameron Mc Jannet grabbed a last-minute goal as Grimsby edged out Cambridge 2-1, pushing themselves into the League Two play-off spots.
It looked like the teams would settle for a draw, but Mc Jannet managed to get the ball over the line four minutes into stoppage time, handing Cambridge just their second home loss of the season.
The Mariners had an early chance when Justin Amaluzor set up Kieran Green, but U’s keeper Jake Eastwood made the save.
They eventually took the lead in the 23rd minute when Reece Staunton’s cross found Green, who powered a header past Eastwood.
Cambridge nearly responded just before half-time when Sullay Kaikai’s corner was flicked on to Mamadou Jobe, whose shot hit the post.
The U’s did level things up in the 41st minute after Adam Mayor made a great run down the left and crossed for Ben Knight to score.
Knight then missed a huge chance to put Cambridge ahead on 60 minutes when Kaikai was fouled and won a penalty, but Jackson Smith saved it with his foot. Then Mc Jannet clinched it late on for Grimsby.
