They trailed, 19-15, with 1:56 remaining in the fourth quarter.
Teams facing similar game circumstances over the years had won only 39.6 percent of the time, according to ESPN win probability statistics. The percentage surged to 73 for the 49ers when Delanie Walker caught Alex Smith's touchdown for the go-ahead points.
That play led all others from the NFC West in our weekly look at which ones were most pivotal.
"To find a way to pull off another one was special," Smith said the 49ers' third fourth-quarter comeback victory on the road this season.
For the second week in a row, the five most pivotal plays in the division came from one game. Last week, the Seattle Seahawks and New York Giants combined for all five, topped by Brandon Browner's clinching 94-yard interception return for a touchdown. This week, with two NFC West teams on bye weeks and St. Louis falling behind early at Green Bay, the 49ers-Lions game provided all the drama.