Glen Johnson did the seemingly unthinkable, dominating Roy Jones and then knocking the all-time great unconscious in the ninth round in Memphis, Tenessee on Saturday.  Johnson threw a right-left combination from that didn’t appear to be all that devastating, but the effect on Jones certainly was.  Jones' head bounced off the canvas and he laid motionless on the canvas for a minute or two.  At the time of the knockout, Jones trailed on the scorecards by scores of 77-75 (twice) and 78-74.  He also was outlanded by Johnson 118 punches to 75 according to Punchstat. Jones appeared to suffer a concussion, and given that he has now suffered two violent knockouts this year and is set for life financially, retirement looks to be the prudent choice. The engaging Johnson, who suffered through more than his share of bad decisions to get to this point in his career at the advanced age of 35 said afterwards, "I'm not the best, I'm just a guy looking to fight the best." Johnson, rated #8 by Boxingtalk coming in, retained his IBF title and hopes to challenge the legitimate world light heavyweight champion, Antonio Tarver.