Bill Parcells defeated fellow Hall of Famer Bill Walsh in their third and final playoff clash, but not before the former Giants coach accused the 49ers coach of cheating in their previous postseason meeting, according to a book to be released next week.

In "Guts and Genius: The Story of Three Unlikely Coaches Who Came to Dominate the NFL in the 1980s," by Newsday columnist Bob Glauber, Parcells approached Walsh before their divisional-round game on Jan. 4, 1987, and told him he knew the 49ers sabotaged their own staff's headsets during San Francisco's first series of the Giants' 17-3 victory the previous year. NFL rules mandate that the opposing team must shut off its headsets in those situations until the coaches' equipment is functioning on the other sideline. Walsh was known to script his plays for his first offensive series; San Francisco's headsets were operating again before the second series.

"Bill," Parcells told Walsh during warmups, "if you pull the same s--- you pulled last year, I'm going to expose you. I'm going to the league with it."

According to the book, Walsh responded with a smile and a wink. "It's just a little gamesmanship," Walsh told Parcells.

The Giants routed San Francisco, 49-3, that day in Giants Stadium on their way to Parcells' first of two Super Bowl victories.

"It was really the start of mutual respect from both of us," Parcells said of Walsh. "He knew I didn't say anything [about the headsets], and I knew he was f---ing with me, and he knew I understood it."

Walsh said afterward, "They played a perfect game. We were shattered by a great team. I believe they will go all the way."

The book reports that 30 of the last 37 Super Bowls (including 17 of the last 18) have been won by Walsh, Parcells, and fellow Hall of Famer Joe Gibbs (the third coach featured), or by former assistants from the Walsh and Parcells coaching trees.