Stretching the glide....undershooting. Very little time to do the right thing, but the BA777 captain on final approach to LHR a few years back, the copilot being PF, and the engines declining to provide power when asked....the captain retracted a stage of flap, they scraped over the fence and all survived.
That was a power failure on approach. Much more difficult if you are faced with EFAT. Too many problems - how to improve the performance of your aircraft which has suddenly turned into a very unhappy glider. No flaps to put away. A useless windmill on one wing at least, acting as asymetrical airbrake. Poor choice of landing areas immediately ahead. No time to restart an engine. They did very well to make it to the river.
When undershooting in a simple glider, with no other problems, you have to lower the nose to INCREASE your speed over the ground, and if done properly this may get you over the hedge. The worst thing to do would be to raise the nose to clear obstacles.