The 49ers' Akers -- who had forced extra time with a 31-yard boot as regulation ran out -- had the best chance with a 41-yard attempt halfway through the overtime. But it sailed wide left, and San Francisco (6-2-1) wouldn't get another chance.
St. Louis (3-5-1) looked like it had won the contest when Zuerlein made good on a 53-yard attempt on the next possession, but the boot was negated by a delay-of-game penalty.
The rookie kicker then couldn't find the range on the resulting 58-yard try.
The tie game was the first in the NFL since a Nov. 16, 2008, draw between the Philadelphia Eagles and Cincinnati Bengals.