Flashback: Keith Olbermann has been calling out Bill O’Reilly's lies for a very long time

With new allegations questioning Bill O'Reilly's reporting on Monday, a segment late last year by ESPN's Keith Olbermann can be seen in a new light.

On Nov. 19, Olbermann named the Factor host his daily "Worst Person In The World," but not because of their long-standing political differences. Instead, a smiling Olbermann tore into O'Reilly's public statements inflating his athletic prowess.

At the time, O'Reilly had given a radio interview talking about his days as a "varsity" football player at Marist College.

"We were undefeated our senior year," O'Reilly told ESPN radio host Dan LeBatard. "That was a pretty good deal."

But Olbermann had debunked that claim as far back as 2005, pointing out that Marist did not field a varsity team until 1978 -- seven years after O'Reilly graduated.

"It was varsity football in the sense of that we played Georgetown, Catholic U., Fordham, Manhattan, Iona," O'Reilly said in his defense. "So, you know, look. You know what it is, guys, you know what it is."

In the months since, O'Reilly has come under more scrutiny for his reporting. On Monday, Mother Jones -- which initiated the wave of questioning earlier this month -- fired back at his assertion that he witnessed people getting shot during a "combat" situation following the end of the Falklands War in Argentina, publishing CBS News footage narrated by O'Reilly that makes no mention of any fatalities:

He says nothing about soldiers chasing him and his crew. And there's no reference to a CBS cameraman being injured. (A reporter who witnesses soldiers shooting protesters and killing many civilians would presumably be compelled to report on those horrors.) His report depicts exactly what other journalists and eyewitnesses have said took place: a violent demonstration in which tear gas and rubber bullets were deployed. In this 1982 report, O'Reilly called the demonstration a "disturbance." But in later years—on his Fox News show, in his writings, and at speaking engagements—he has claimed that the event was a bloody melee that amounted to "combat" in a "war zone."

In the past, O'Reilly has attacked Mother Jones' David Corn as a "guttersnipe" and a "liar." On Monday, however, he did not address the latest story on his program.

Watch Olbermann's commentary on O'Reilly's days as an athlete, as posted by ESPN, below.