George Kittle was on fire in the San Francisco 49ers’ 42-10 win over the Dallas Cowboys on Sunday.

Kittle had three catches for 62 yards – all three receptions were for touchdowns. He caught three of Brock Purdy’s four touchdown passes on the night and the team remained undefeated.

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After one of the scores, Kittle revealed on Instagram the shirt he was wearing underneath his jersey that added the extra insult against the team’s NFC rivals.

"F--- Dallas," the shirt read.

Kittle’s been having a great start to the season. The four-time Pro Bowler has 17 catches for 215 yards and picked up his first handful of touchdowns during the game against the Cowboys.

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San Francisco dominated on offense and defense. The team picked Dak Prescott off three times and forced a fumble. The team hasn’t dropped a regular-season game since last year.

"I knew it was our biggest game so far this year as far as nationally and just media wise and the hype," 49ers coach Kyle Shanahan said. "Sometimes you worry your team can get too up for stuff.... They were so locked in all week. They didn’t make too big a deal of this game and were ready to go."

After Sunday, the 49ers’ offense was ranked second in points scored and third in yards gained. The team is also first in points allowed and third in yards allowed.

The Associated Press contributed to this report.