KANSAS CITY, Mo. -- Patrick Mahomes recalled thinking he would be ready for whatever the opposing defense threw his way during his first season opener as the Kansas City Chiefs' starting quarterback in 2018.

"At the time I felt very prepared but looking back on it I feel like I wasn't prepared at all," Mahomes said Wednesday as the Chiefs began their preparations for his fourth season opener. They face the Cleveland Browns on Sunday at Arrowhead Stadium (4:25 p.m. ET, CBS).

"I kind of just went out there and started slinging it and Tyreek [Hill] was running all over the field. I definitely feel more prepared now just because I have a better grasp of the offense. I have a better grasp for what it takes to win football games."

Mahomes and the Chiefs didn't fare poorly that day. Mahomes threw four touchdown passes in a 38-28 win over the Los Angeles Chargers.

He's been similarly sharp in September games ever since. Mahomes is 10-0 in the season's opening month the last three seasons with 3,304 yards, 32 touchdowns, zero interceptions and a passer rating of 124.4.

The Chiefs, meanwhile, haven't lost a season-opener since 2014. They have started the season 5-0, 5-0, 4-0 and 4-0 in the past four years.

"We just stress the importance of starting the season fast," Mahomes said. "We have a very tough training camp as everyone knows where we really compete and go at it every single day of practice. That prepares us to be ready to go from Day 1.

"We know if you lose a game in September it can cost you at the end of the season as far as seedings and trying to get into the playoffs. We just stress the importance knowing we're playing a lot of really good football teams early in the year."

The Chiefs give their defensive opponents plenty to prepare for any time of the season but are more unpredictable than usual in an opener. They extensively used jet-sweep action with the speedy Hill to much success in the 2018 win over the Chargers.

The Chiefs ran the ball (34 times) more than they tried passing it (33) in last year's opener against the Houston Texans. That's an unusual development for them since Mahomes took over as the starting quarterback.

"Being able to present a new look for the [opposing] defense, maybe something they haven't seen before, just wrinkles to a lot of the stuff we've done and kind of puts them in a reactionary position early on," tight end Travis Kelce said. "It's an on-going process to keep trying to be the one that's ahead in terms of the mind game or the chess game."

Mahomes said of the playbook each season, "It's so different. That's the biggest thing. Obviously teams change every year and so the playbook changes every year. That's what's kind of kept us having success. Every single year we're coming up with new plays. We're not staying stagnant or where we're at."