Buffalo's defense came into the 2014 season a top 10 unit. They were not foreign to having success finishing second in the league in sacks in 2013, and setting a franchise mark in that category in the process. There were however, some glaring deficiencies, run defense and third down defense being the most notable. Under a new coordinator for a fifth straight season Buffalo took another change in stride and became a complete defense.

Buffalo finished the season as a top five defense, ranking fourth overall, and finished in the top five in a host of different defensive categories. Chief among them, sacks (1st – 54), third down percentage (1st – 33.18), yards per play (3rd, 4.86), passing defense (3rd – 205.8), takeaways (3rd – 30) points per game (4th – 18.1) and first downs per game (5th – 18.9).

The statistic that held the most meaning for Buffalo's defenders was points allowed. The other stats have their value, but don't come close to the significance of the points a unit can keep off the board as a defense.

While the Bills stood fourth in points per game allowed, when you strip down Buffalo's points allowed to those only scored by opposing offenses, the Bills ranked second in the league allowing just 271 on the year. It was a sizable improvement from 2013 when Buffalo ranked 20th in that category.

"It was a high standard we set for this defense," said Aaron Williams. "And we made sure to keep each other accountable."

Many attributed the success to the unit's improved run defense. Languishing near the bottom of the league for the majority of the past decade, the Bills finished a respectable 11th against the run, shaving more than 25 yards off their average allowed in 2014.

"We made that a point of emphasis during (training) camp where we're not going to let anybody run on us," said Marcell Dareus. "We were going to do the best we could just to get the run defense the best we possibly could. Best in the league was the goal."

Though they did not finish in the top 10 in run defense, the 1,703 rushing yards allowed by the Bills was the lowest total since Buffalo's 2004 defense. That Buffalo team finished second in the league against the run that year and allowed about 100 yards less (1,604).

Full credit went to a front seven that got a performance from a defensive line that met their expectations. The linebacking unit behind them however, exceeded the predictions many outside observers had for the group.

Knowing Kiko Alonso was lost for the year after tearing his ACL in July, Buffalo was relying on some combination of Nigel Bradham, Keith Rivers, Brandon Spikes and rookie Preston Brown to be steady and reliable. They proved to be that and more.

Bradham did a complete 180 with his career proving to be an every down playmaker. Whether it forcing fumbles, logging a sack on a blitz or covering sideline to sideline, the third-year player emerged as a dependable force logging more than 100 tackles.

Spikes did exactly what he was brought in to do, provide some veteran leadership and sure up the team's run defense. And Brown developed quickly as a rookie drawing comparisons to the rapid ascent of Alonso the year before. The third-round pick led the team in tackles (108), and like Bradham proved to be a three-down player.

"It was probably the hunger," said Bradham of the success of the linebacking corps. "We just had to do it. It just had to be done. I think that was the difference."

Of course the men in front of them made it easier for Buffalo's linebackers to run and hit. As effective as Buffalo's defensive line was against the run their calling card was still the quarterback takedown. The Bills defensive line had 48 of the team's 54 sacks on the year, which led the league. Combined with their team record 57 sacks in 2013, their 111 sacks is the most in a two-year span since the 2000-2001 New Orleans Saints (119).

Mario Williams and Marcell Dareus put together single-season career highs in the sack category with 14.5 and 10 respectively. Both earned Pro Bowl honors as well as 1st team All-Pro. Kyle Williams, who earned the fourth Pro Bowl nod of his career, felt their success up front was due in large part to the men in Buffalo's secondary.

"We couldn't do anything that we do without what our secondary does," Williams said. "Those guys get on guys and they give us opportunities and they get picks because we get pressure. We get sacks because they're covering guys up.

"Our linebackers are the same way. Literally playing together and playing off of each other is not just a front four thing. It's an everybody thing. And in the past even though we've had good players that's been what we've kind of missed in run defense is getting feel for what we're doing. Our front seven has really cleared that up. We all couldn't do what we do without them. It's truly everybody all 11 playing off each other."

There's no question Buffalo's secondary was opportunistic. Their takeaway total of 30 was third-best in football and the cornerbacks took the lead. Leodis McKelvin finished as the team leader in interceptions with four despite missing the last six games with a fractured ankle. Stephon Gilmore had a strong second half of the season to finish with three INTs and veteran Corey Graham proved to be a valuable signing in the offseason. He led the team in pass breakups, had a pair of INTs and lined up at both cornerback and safety.

"Very good group," said Graham of the secondary. "We got better and better as the season went on. Guys went out and competed their butts off especially in a scheme when you're in man-to-man pretty much every play. It's a very good group. We got better. I look forward to what it's going to be like having the opportunity to play with these guys. It's a special group. The more time we get together the better we're going to be. Get more on the same page I think we can be one of the best there is."

Nickell Robey finished second on the team in pass breakups with 10, building off his solid rookie season as the slot corner, and Da'Norris Searcy in his first full-time role at safety was productive logging three interceptions and finishing sixth in tackles. He and Aaron Williams were a big reason why the Bills ranked second in the NFL in 20-plus yard completions allowed giving up just 36 on the year.

"I would say the big emphasis was that we didn't want any deep balls thrown on us," said Searcy. "We wanted to keep everything in front of us. We felt like if we could keep it in front of us we could see it and make a play on it."

For the players on the defensive unit 2014 was about dedicating themselves to being consistent. In most cases they delivered and they have the numbers to prove it.

"You could tell we were a lot more intense defense," said Bradham. "We played with a lot more passion. Our intensity definitely stayed the same every game, every week. There wasn't ever a drop off."

Though there are some key free agents to address like Jerry Hughes and Searcy, the addition of new head coach Rex Ryan and his defensive staff, coupled with the return of Kiko Alonso in 2015 has the unit eager to prepare for next season.

"Our defense can get like ten times stronger," Bradham said. "It's a great thing to have this much talent on a team because we know we can be the best unit in the league."