HOUSTON -- The Houston Texans' defense thrived in a playoff victory over the Oakland Raiders. But that was against Connor Cook, a rookie quarterback making his first NFL start.

In Saturday's divisional-round matchup against the top-seeded New England Patriots, Houston will face a much tougher challenge -- Tom Brady. Texans coach Bill O'Brien, who worked closely with Brady as a coach in New England, did not mince words when talking about the three-time Super Bowl MVP.

"To me, he's the best quarterback to play the game," O’Brien said. "He's done it with different types of teams, different teammates. He's a great quarterback. So in preparation for him, it's very difficult."

Brady did not play in the Week 3 matchup between the Texans and Patriots because he was serving the third game of a four-game suspension to start the season. In the 12 regular-season games he did play, he was of MVP caliber. Brady completed 67.4 percent of his passes for 3,554 yards, 28 touchdowns and just two interceptions, and his passer rating was 112.2.

O'Brien worked under Patriots coach Bill Belichick from 2007 through 2011. He was the offensive coordinator during the final season and the quarterbacks coach in the two before that. O'Brien praised Brady's preparation and mindset.

"He's a very intelligent guy," O'Brien said. "He's a guy that's very well-prepared. He's seen it all. I think it's important for us to just make sure we know what we're doing, execute our game plan and make sure we're doing our job."

Houston's secondary is one of the best in the NFL; the Texans ranked second in the league by allowing just 202 passing yards per game during the regular season.

Tom Brady is "the most poised quarterback in the NFL," Texans defensive end Jadeveon Clowney said. Greg M. Cooper/USA TODAY Sports

One way the Patriots could rattle Brady is by pressuring him in the pocket. New England's offense, though, is known for quick throws. The Patriots' offensive line is a stout unit as well, allowing 24 sacks in the regular season, fifth-fewest in the NFL. Houston's defense notched 31 sacks during the regular season, tied for seventh-fewest in the league.

"The biggest challenge is probably trying to get to him," cornerback Kareem Jackson said. "They definitely do a great job of protecting him. Like you said, he's Tom Brady. He definitely will be one of the greatest quarterbacks to ever play the game.

"For us, it's all about going out there and executing the game plan. [Defensive coordinator Romeo Crennel] will give us some great stuff to go out there and be successful with."

But even when teams are able to get pressure on Brady, he usually finds a way to get off the throw.

"I just think the guy's the most poised quarterback in the NFL," defensive end Jadeveon Clowney said. "Playing him, he doesn't get rattled at all most of the time. He just keeps staying calm, and that's what makes him so good. He just stays calm back there. Even when you do get the pressure, he steps up and makes the best pass."

The Texans head to New England coming off an impressive defensive performance, albeit against a third-string rookie. They sacked Cook three times, forced him to throw three interceptions and held him to just 3.6 yards per attempt. Obviously, the challenge is going to be greater against Brady, and Houston is relishing the opportunity.

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"You know you're going against the best and it's a big opportunity because you want to be at your best and try to make a play against him," cornerback A.J. Bouye said. "And at the end of the day it all comes down to winning and changing the game on defense and getting the ball in our offense's hands."

O'Brien knows how Brady prepares for games, and he is aware the four-time Super Bowl champion will have a good idea of what the Texans will present defensively.

"We're not going to show him anything that he hasn't already seen," O'Brien said. "He's been doing it for years, 17 years or whatever it is. I mean, that's part of what makes him who he is. He's seen it all. He's very well-prepared. He's played against a lot of these players. He's played against this scheme.

"We just need to kind of do what we do and execute and play every play. Be very focused on every single play, I think that's big for us."