JACKSONVILLE, Fla. -- After the Houston Texans' 0-3 start, head coach Bill O'Brien preached the ultimate football cliché: That if his players took it one game at at time and continued to show improvement, the team would be where it wanted to be by the end of the season.

It's only Week 7, but the Texans have certainly taken that to heart. On Sunday against the Jacksonville Jaguars, Houston played its most complete game of the season, a 20-7 victory. The Texans finally played complementary football and dominated an opposing team for the majority of the game.

Houston was in last place in the AFC South after three games, but after its victory in Jacksonville -- its fourth in a row -- the Texans have sole possession of first place in the division.

The Texans are just the sixth team in the Super Bowl era to win four consecutive games after starting 0-3, according to ESPN Stats & Information research. Only one of those teams, the 1998 Buffalo Bills, made the playoffs.

So how have they done it?

During the winning streak, the Texans defense has looked much better, especially in the past three weeks, when Houston has allowed just 36 total points. It allowed 74 points during its 0-3 start.

The Texans defense has gotten a strong pass rush for most of the season -- led by J.J. Watt and Jadeveon Clowney -- but in the past four games, the secondary has shown a lot of improvement as well. In the past two weeks, the Texans have forced three lost fumbles and have intercepted three passes, including one for a pick-six.

"I think it's a great defense and I think they played really well," head coach Bill O'Brien said.

And against the Jaguars, the Texans were finally able to have success on the ground. On Sunday, Houston relied heavily in the first half on the running game, something that had not been successful during this winning streak and something O'Brien has said the team needs to get better at to take some pressure off of quarterback Deshaun Watson.

"I think any time you can run the ball, I think that's a big deal in this league, especially for us," O'Brien said. "I think that helps us because it helps a lot of different things, like being in play-action, being in manageable third downs. I think that running the ball is an important thing, and our guys did a nice job today."

Lamar Miller carried the ball 22 times for 100 yards and a touchdown against the Jaguars. Scott Halleran/Getty Images

Houston did that early, as running back Lamar Miller ran for 75 yards in the first half, the most before halftime by a Texans running back since Week 1 of the 2016 season. He finished the game with 100 yards on 22 carries and had a touchdown.

Watson did his part to take advantage of the success on the ground, playing through injuries to his ribs and lung. He completed 12 of 24 passes for 139 yards and a touchdown and did not throw an interception for the first time this season.

While the first three games of their winning streak could have gone either way -- victories in Week 4 against the Indianapolis Colts and Week 5 against the Dallas Cowboys came in overtime by a field goal -- the Texans were able to beat the Jaguars comfortably. Week 7 marked the first game the Texans have won this season by more than a touchdown.

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There's certainly still plenty of season left -- and the Texans hold only a one-game lead in the division -- but Houston has a favorable schedule the rest of the way. According to ESPN's Football Power Index, entering the game, Houston had the second-easiest schedule remaining. If the Texans can continue to play complete games like they did Sunday against the Jaguars, Houston should be able to take advantage of the schedule the rest of the way.

But even as the leaders of the AFC South, Watson cautioned that the Texans still have a lot of work to do.

"It's cool for now," Watson said. "But we got another big one Thursday. Right now we're going to celebrate it and then turn around, wake up Monday, and get ready for Miami and really try to separate ourselves [in the division].

"We can really do some damage and separation [these next two weeks], but just continue to take it one day at a time and continue to fight and continue to get better."