CINCINNATI >> The Bengals have fired defensive coordinator Teryl Austin today, a day after a 51-14 loss to the Saints , and put head coach Marvin Lewis in charge of trying to resuscitate a historically bad unit.

New Orleans scored on every possession except the last one — when it took a knee while in field-goal range — during its rout at Paul Brown Stadium, prompting the Bengals (5-4) to fire a coordinator in-season for the second year in a row.

The Bengals have given up at least 500 yards in three straight games — a first in the Super Bowl era — and are on pace to give up an NFL record for yards in a season. In the past four games, Cincinnati has allowed 481, 551, 576 and 509 yards.

The Bengals are on pace to become only the second team in NFL history to give up 7,000 yards in a season, along with the 2012 Saints.

It’ll be the second time during his 16-season tenure in Cincinnati that Lewis has gotten directly involved in the defense.

The Bengals hired him in 2003 in large part because of his reputation for defensive coaching — he coordinated the Ravens’ Super Bowl-championship defense in the 2000 season. Defense has been a regular challenge during his tenure.

Lewis became so frustrated with the defense in 2004 — his second season — that he took over play-calling from coordinator Leslie Frazier during a game against Cleveland. The Bengals lost 34-17 and Lewis left the defense in Frazier’s hands the rest of the way, and then fired him after the season.

Now, he’s back in charge. Players were told of the change during an afternoon meeting.

“I will be coordinating the defense from here on out and I am excited to do that,” Lewis said in a statement.

Lewis hired Austin from Detroit after defensive coordinator Paul Guenther left to join Jon Gruden with the Raiders. The Bengals gave up a lot of yards while opening the season 4-1, with the defense scoring four touchdowns off fumble and interception returns to overcome the poor showings overall.

With injuries sapping the defense during a stretch of games against the NFL’s top offenses — Pittsburgh, Kansas City, Tampa Bay and New Orleans — the unit imploded on the field. The Saints scored touchdowns on all five first-half possessions Sunday, and moved the ball easily even when they were running out the clock in the fourth quarter.

The Bengals matched the club record by giving up 28 points in the second quarter. The 51 points allowed were one shy of the club record.

Austin is the fourth coordinator fired in the NFL this season. Tampa Bay fired defensive coordinator Mike Smith, Arizona fired offensive coordinator Mike McCoy, and the Browns fired head coach Hue Jackson and offensive coordinator Todd Haley.

Last year, the Bengals fired offensive coordinator Ken Zampese after an 0-2 start, but the Bengals missed out on the playoffs for the second year in a row. Lewis got a two-year contract extension after the season even though he’s 0-7 in the playoffs — an NFL record for futility.