The Giants appeared to be finished. They had fallen behind the 49ers, 20-10, in the third quarter and were struggling to match the effort of a young San Francisco team that did not seem to be aware that it was engaged in a race to the bottom of the N.F.L.
But something clicked at that point for the previously hapless Giants, as Eli Manning and the offense came alive. Manning put together two second-half touchdown drives — the second one finding the end zone with less than a minute left — for a 27-23 victory that gave the visiting Giants a second win and sent Nick Mullens and the 49ers back to the drawing board.