The 49ers would score touchdowns on each of three Cowboys turnovers, all before halftime. Even though the Cowboys held a significant edge in 1st quarter time of possession (13:26 to 1:34), the 49ers had a 21-3 lead due to the turnovers. With the 49ers up 28-3, the Cowboys would find themselves with their largest halftime deficit in a home opener ever. Although the 49ers would not score again in the second half, they would only hold the Cowboys to 14 more points, and win the game.

Answer this question based on the article: How many points did Dallas trail by at the half?
18