The Baltimore Ravens did something that's never been accomplished in the 16-year existence of the franchise: They didn't commit a penalty.

Baltimore wasn't flagged once in Sunday's divisional playoff game against the Houston Texans. Any time you don't get called for something as small as a false start, it should come as a surprise. But it's especially surprising that it occurred during a playoff game when players are amped up.

"To me, it’s emotional smarts," coach John Harbaugh said during Monday's session with reporters. "It’s understanding when to be aggressive and when not to be. Basically, it’s between the whistles. The rest of it doesn’t matter."

This Baltimore team has been disciplined when it comes to penalties. The Ravens committed 92 penalties during the regular season, which was the ninth fewest in the NFL and three shy of the team record.

Baltimore has been more diligent about penalties ever since owner Steve Bisciotti spoke about the team after the 2009 season. It's no coincidence the Ravens' penalties have decreased from 115 in 2009 to the low 90s in 2010 and 2011.