KANSAS CITY, Mo. -- Patrick Mahomes had what for him was a slow day on Sunday against the San Francisco 49ers. He threw for just three touchdowns in the Chiefs' 38-27 victory at Arrowhead Stadium.

The three touchdown passes, which all happened in the second quarter, still put Mahomes in the record book. He has 13 touchdown passes, setting a record for the first three games of an NFL season.

Denver's Peyton Manning had the old record of 12, set in 2013.

"He's the Showtime Mahomes,'' tight end Travis Kelce said. "He keeps surprising everybody every single week, even his teammates. It gets us rolling, playing with confidence, and that stuff is contagious and we just keep it rolling from there.

"Man, it's a blast. I'm not gonna lie. Every time we come to the sidelines, everybody's excited about what just happened on the field. We've all never been a part of something like this ... It's a fun ride right now.''

Mahomes threw touchdown passes of 12 yards to Demetrius Harris, 4 yards to Chris Conley and 12 yards to Sammy Watkins to break Manning's record and put the Chiefs ahead 35-7 late in the first half.

Mahomes' 13 touchdown passes have gone to nine different receivers. Nine receivers to score touchdowns is also a record for the first three games of a season, according to the Elias Sports Bureau. The Chiefs had touchdown catches from seven receivers all of last season.

"I've seen these guys in practice,'' Mahomes said. "These guys I have at the receiver position can really get open. It's hard for teams to have to play every single one of them. I know if I get through my reads there will be someone open. The offensive line is blocking so well I can kind of sit in the pocket, get through my whole entire read and find the open guy.''

The touchdown pass to Conley was spectacular. Pressure forced Mahomes out of the pocket to his left, but a defender forced him to reverse field. Mahomes then threw a laser to Conley in the back of the end zone while running to his right.

"We had a play called and it kind of broke down, but that's the magic of Pat,'' Conley said. "He's not necessarily looking to run ... He can throw those fastballs.''