Gregg Williams coached against the New England Patriots from 2001-03 as head coach of the Buffalo Bills.
Although his record was just 1-5, he developed an understanding of what the Patriots do offensively.
Williams will bring that experience on Sunday when the Redskins take on the 7-0 Patriots at Gillette Stadium.
He sees a Patriots offense that is operating at peak efficiency.
"Their execution is outstanding," he said. "People perceive that they have an awful lot of plays. They just execute the ones they have very well. Tom [Brady] is playing very well. Obviously the weapons he has in the passing game have been very complimentary to his skills and to what they're doing.
"They are running the same play concepts, the same things they have done for a long time--similar to us. We're running the same play concepts we did last year, but we have better personnel. They have better personnel executing their offense right now."
For Williams, the key to the game is which unit executes the best.
His bag of tricks includes blitzing, but his defensive cast has the versatility to play a Cover 2 scheme, especially with the hard-hitting Sean Taylor in the secondary.
The presence of Taylor, rookie LaRon Landry and veteran Pierson Prioleau will be key as they provide the physicality needed to level punishing hits on wide receivers and disrupt the Patriots' passing game.
"They're going to know what we do, and we're going to know what they do," he said. "Can we win some of the matchup battles? We'll see."
Williams won't say it, but he has to relish the opportunity to coach against the Patriots again.
New England enters the game with an offense that is outscoring opponents by a 40-17 clip. The offense is ranked first overall in the NFL and first in passing offense.
Tom Brady has 27 touchdown passes, a record pace. Randy Moss has 44 catches and 10 touchdowns, Wes Welker has 47 catches and five touchdowns and Donte Stallworth has 22 catches and three touchdowns.
It's the third time in the Redskins' last four games that they face the league's top-ranked passing offense.
The Redskins held the Detroit Lions' passing game to just 106 yards in a Week 5 win. One week later, at Green Bay, the Redskins held Brett Favre and the Packers to just 188 passing yards.
Brady and the Patriots are averaging 299.4 passing yards per game in their 7-0 start.
"I have tremendous respect for Bill Belichick and his coaching, even back in the days when we had battles when he as was at Cleveland and I was with the Oilers in the early 1990s in the AFC Central," Williams said.
"You always knew every single week that no matter what your personnel was, no matter what their personnel was, you were going to have to earn every inch.
"Those games are fun to be in because you appreciate that and you respect each other as coaches in those types of situations."