Buffalo Bills coach Sean McDermott earned his job based on his ability as a defensive coordinator, which is why you knew it was only a matter of time before the Bills became a dominant defense.

That time is now.

The Bills became the third team since 1990 to get two shutouts in the first four games of a season when they blanked the Houston Texans 40-0 on Sunday. The Bills lead the NFL in scoring defense and total defense, giving up 11 points per game.

That defense, coupled with the explosive offense led by Josh Allen, has the Bills up to the fourth spot in my Power Rankings this week, the top-ranked team from the AFC.

The Bills haven't exactly played great offenses or quarterbacks. The shutouts came against rookie quarterback Davis Mills of the Texans and the Dolphins in Week 2 when Tua Tagovailoa was knocked out of that game early with an injury. Their other two games were against an aging Ben Roethlisberger with all his issues and Washington's Taylor Heinicke.

That changes this week in a big way. It's Patrick Mahomes week.

The Bills lost to Mahomes and the Kansas City Chiefs twice last season, the last time in the AFC Championship Game in Kansas City. In those two games, Mahomes threw five touchdown passes, no interceptions and was sacked just twice.

With the Bills unable to influence Mahomes in the championship game, Bills general manger Brandon Beane and McDermott made addressing the pass rush a priority in the offseason. They used a first-round pick on defensive end Greg Rousseau and a second-round pick on Boogie Basham. Combine that with the improvement of last year's second-round pick A.J. Epenesa and the return of COVID-19 opt-out Star Lotulelei and and you can see why the Bills are tied for sixth in the league with 12 sacks.

Ten different Bills have sacks, led by Lotulelei and Rousseau with two each. Basham got his first sack against the Texans.

To beat Mahomes, you have to hit Mahomes, which the Bills watched Tampa Bay do in the Super Bowl. That's why the changes were needed. This game will feature two explosive quarterbacks in Mahomes and Allen, but it will come down to the defenses, the one that plays best will be team that wins the game.

Home-field advantage could certainly be at stake here. The importance of that is simple when you consider McDermott is 2-0 in the postseason at home and 0-3 on the road. Chiefs coach Andy Reid is also 0-2 on the road in the playoffs as coach in Kansas City.

Playing in Arrowhead for a chance to go to the Super Bowl is a tough task. But playing at Buffalo in January can be downright brutal, which is why the Bills had to revamp the pass rush to try to beat Mahomes.

Biggest Movers
8 Cowboys
9 49ers
1 Cardinals They have earned the right to be in the top spot. They dominated the Rams on the road and Kyler Murray is in the MVP conversation. 1 4-13-0
2 Packers After that awful showing in Week 1, they have turned their season around quickly. At 3-1, they have a nice hold of the division after the first month. 1 9-8-0
3 Buccaneers It wasn't easy in New England, but they found a way. They showed they can win games, even if Tom Brady isn't on top of his game. 1 9-8-0
4 Bills The Kansas City game will be a proving ground for the Bills. If they win, they show the league they are the class of the AFC. 1 11-6-0
5 Browns It wasn't pretty at Minnesota, but they found a way. That's the sign of a good team. They just keep fighting -- even on bad days. 3 11-6-0
6 Rams They put so much into the Tampa Bay game, so there had to be a letdown against the Cardinals. But to that degree? Now comes a tough trip to Seattle. 5 10-7-0
7 Chargers They beat up on the Raiders Monday night. If the defense plays like that, they will be a real threat in the AFC. 4 5-12-0
8 Cowboys After losing their opener on the road, they have really come on strong. The biggest surprise is how well the defense is playing for coordinator Dan Quinn. 8 12-5-0
9 Chiefs That offense we saw in Philadelphia is what we expect to see. But the defense still has major issues and now here comes the Bills for a real test. 3 11-6-0
10 Ravens That was an impressive road victory against the Broncos. The defense had its best game of the season, which is a good sign. 3 13-4-0
11 Raiders Their prolific offense was shut down against the Chargers. Was that an aberration or a sign of things to come? 5 8-9-0
12 Panthers After suffering their first loss of the season against Dallas, they get five consecutive games against teams currently with one victory each. That's a soft schedule and a way to get back on track. 3 2-15-0
13 Bengals Is their 3-1 record legitimate? They are improved, but we will know how much improved this week against the Packers at home. 4 9-8-0
14 Seahawks They won a had-to-have-it game against the 49ers with an improved defensive effort. That's something they had to see. 5 9-8-0
15 Broncos The offense was dreadful against the Ravens, especially after Teddy Bridgewater went down with a concussion. At 3-1, they still have to like their fast start. 5 8-9-0
16 49ers There is a chance Trey Lance starts for Jimmy Garoppolo in this one. Whoever starts, this is a big game in terms of the division race. 9 12-5-0
17 Saints This team is hard to figure out. They look great one week and awful the next. They have to get more from their passing game in terms of chunk plays. 3 9-8-0
18 Titans That was a terrible loss at the Jets, even with all the injuries. That's the kind of loss that can come back and haunt them in a big way. 3 6-11-0
19 Patriots They showed well against the Buccaneers. The best news is Mac Jones is improving each week. 1 4-13-0
20 Commanders They won a game at Atlanta, but the defense still has major issues. That unit was supposed to be carrying this team, but it's not come close to that. 3 4-13-0
21 Bears Justin Fields got his first NFL victory against the Lions with a solid showing. But he goes back to the bench if Andy Dalton is back, which is a questionable move. 4 7-10-0
22 Colts Winning at Miami was a must for this team with their brutal schedule coming up. The defense came up big, showing well for the first time this season. 4 9-8-0
23 Vikings That explosive offense took a break against the Browns as Kirk Cousins struggled after the first quarter. At 1-3, the first month hasn't been kind to this group. 5 7-10-0
24 Falcons At 1-3, they head to London to play the Jets. The offense played well against Washington, but the defense let them down. It's been a tough start for first-year coach Arthur Smith. 3 7-10-0
25 Giants That was a nice showing by Daniel Jones on the road against the Saints. Throwing for over 400 yards in an upset victory says a lot about his growth. 3 6-11-0
26 Dolphins Without Tua Tagovailoa, they are so limited on offense. Jacoby Brissett just can't get it going in his place. At 1-3, they now head to Tampa for a tough game against the Bucs. 5 11-6-0
27 Eagles At 1-3, they are quickly falling behind in the division race. Jalen Hurts did some really good things against the Chiefs, which gives them hope. 3 11-6-0
28 Steelers They just can't get the offense going. In a division with three 3-1 teams, they face huge odds to get back into the race. 6 10-7-0
29 Texans Davis Mills was simply overmatched on the road against the Bills. They need Tyrod Taylor back as quickly as they can get him. -- 10-7-0
30 Jets It looks like Zack Wilson seemed to find some things against the Titans in the second half. That could be the start of him gaining confidence in a big way. 2 7-10-0
31 Lions They compete in games, but it's just not enough. This first year will include a lot of losing for Dan Campbell. 1 12-5-0
32 Jaguars Urban Meyer's NFL career is off to a shaky start. His team hasn't won and the video from his night on the town doesn't help his standing. He needs a victory in the worst way. 1 9-8-0