Three takeaways from 49ers' blowout win over Cowboys on 'SNF'

The San Francisco 49ers closed out Week 5 with a one-sided victory over the Dallas Cowboys on "Sunday Night Football," 42-10. Exiting as one of only two remaining undefeated teams in the NFL, here are three takeaways from the 49ers' big win: 

Brock Purdy outclassed Dak Prescott in primetime: With the 49ers favored by only four at home, Purdy made sure it wasn't that close, heavily outperforming Prescott in what some called his stiffest test of the early season. 

Purdy tortured the Cowboys' defense, finishing the night 17-of-24 for 253 yards and four touchdowns while sporting a robust 144.4 passer rating. Purdy's performance helped him join Kurt Warner, Peyton Manning and Tom Brady as the only quarterbacks to lead their team to eight straight games of 30 points or more, per The Athletic. 

Meanwhile, Prescott crumbled under the pressure from the 49ers defense. Prescott had a tough time finding a rhythm, recording an abysmal 51.6 passer rating, completing 14-of-24 passes for 153 yards with a touchdown and three interceptions. 

49ers defense feasted on Cowboys: While the offense lit up the scoreboard, totaling 421 yards, the defense took care of things on the other end of the ball. After the Cowboys managed only 93 first-half yards, the 49ers ended any hopes of a comeback, holding Dallas to only 104 yards after halftime.  

Giving up only 4.0 yards per play to the Cowboys, the 49ers D was also opportunistic, finishing the night with four sacks, three interceptions and a fumble recovery. 

Loss for the Cowboys hurts a little more: At 3-2, the Cowboys' season isn't over, but their path to the postseason is a little more difficult after the loss. The Cowboys now find themselves two games back in the division, trailing the still-undefeated Philadelphia Eagles, who improved to 5-0 after a 23-14 win over the Los Angeles Rams earlier in the day. 

While the deficit isn't surmountable, it's not ideal five weeks into the season, and it puts extra pressure on the Cowboys to get back in the win column. That won't be the easiest task as they head back on the road next week to take on a tough Los Angeles Chargers squad on "Monday Night Football." 

Bonus Nugget — Christian McCaffrey continues historic scoring stretch: McCaffrey found the endzone again in Week 5, making it 14 consecutive games with a touchdown for the Niners standout back. Late in the first half, McCaffrey capped off a nine-play, 75-yard drive with a rushing touchdown from one yard out. 

According to ESPN Stats and Info, McCaffrey moves into a tie with former Cowboys great Emmitt Smith for the fourth-longest streak in NFL history. 

In a blowout victory, the 49ers didn't lean solely on McCaffrey, who had 51 yards rushing yards off 19 carries and two receptions for 27 yards, but he still managed to find his way to paydirt again.