(Seattle) Christian McCaffrey had 114 rushing yards and two touchdowns in the first half, and the San Francisco 49ers defeated the Seattle Seahawks 31-13 on Thursday night.

McCaffrey helped his team build a 21-point halftime lead.

The 49ers have won their last four games against their National Association West rivals and are two games ahead of them.

The 49ers won their second straight game after losing three straight. It was a 10th straight win against a team from the West section of the Nationale.

McCaffrey was sensational, scoring touchdown runs of eight yards and one yard, helping the 49ers head into the locker room with a 24-3 lead at halftime.

Deebo Samuel also completed a rushing touchdown, this one for two yards during the 49ers’ first offensive drive. Quarterback Brock Purdy impressed in the first half with 15 of 20 completions.

Purdy was the victim of an interception early in the third quarter, which the Seahawks returned for a touchdown. However, the 49ers quarterback did not make another mistake. Purdy capped his night with a 28-yard touchdown pass to Brandon Aiyuk with 7:51 left, seeing some Seahawks fans have had enough and head for the exit.

Purdy finished the game completing 21 of 30 passes for 209 yards.

Geno Smith was at his post, but was physically damaged, having not finished the game against the Los Angeles Rams last Sunday. Smith left the game in the second half due to an injury to his right arm, near the elbow.

Smith completed 18 of 27 passes for 180 yards. He was the victim of six quarterback sacks and an interception. The Seahawks’ first five possessions on offense totaled just 15 yards.

The Seahawks have scored just three touchdowns on offense in their last four games, and just one in their last eight quarters.