PITTSBURGH -- The Kansas City Chiefs expected a lot from Patrick Mahomes after installing him as their starting quarterback this season. But they didn't quite expect all that he has delivered thus far, including Sunday's 42-37 win over the Pittsburgh Steelers.

"I don't think that you could expect more from anyone," said wide receiver Chris Conley, who caught one of Mahomes' team-record-tying six touchdown passes on Sunday. "Pat's come here and handled himself extremely well. The level of confidence and poise that this kid has ... I haven't seen it anywhere. He's continued to go in, learn and get better every day and then come out on the field and execute.

"You can't ask him to do anything else. He's handled the times where he's made the plays really well. He's handled the times where he hasn't. That speaks volumes."

Mahomes was close to flawless on Sunday, when he threw more touchdown passes than incompletions (five). He was 23-for-28 for 326 yards and a passer rating of 154.8, or less than four points from the highest possible number.

Mahomes, who threw four touchdown passes last week in Kansas City's season-opening win over the Los Angeles Chargers, set an NFL mark for scoring throws in the first three games of a career. The old record was eight, shared by Marcus Mariota and Mark Rypien. Mahomes started the final regular-season game as a rookie last season but didn't throw for a touchdown.