Brock Lesnar Retirement: Where UFC Star Ranks Among All Time Greats

Although former UFC champion Brock Lesnar's career was over as quickly as some of his fighting adventures inside the Octagon, his greatness at the sport's highest level must be taken into consideration when ranking the all time great heavyweight title holders in UFC history.

The 34-year-old retired on Friday night immediately following his first-round TKO loss to 31-year-old Alistair Overeem, who was making his UFC debut. 

Lesnar's career was marred by a debilitating intestinal disease known as diverticulitis, which forced him away from the cage for months at a time during his four-year MMA career.

But even still, Lesnar's crushing style of taking opponents to the mat and finishing them off like an untrained animal remains one of the more unique the sport has ever seen.

Despite how quietly Lesnar went out on Friday night, and how disappointing his final fights were for fans, the former college wrestler had an excellent though short run of dominance.

My top five UFC heavyweight champions:

No. 5: Andrei Arlovski (17-9)

Arlovski was the UFC heavyweight champ for a stretch from 2005 to 2006 and has always been a knockout threat. Thirteen of the Pit Bull's 17 career wins have come via knockout.

No. 4: Brock Lesnar (5-3)

Even though Lesnar's career was short-lived, he held the UFC heavyweight crown for more than 700 days and successfully defended his title twice against former champion Frank Mir and previously undefeated Shane Carwin.

No. 3: Tim Sylvia (30-7)

The 6'8" Sylvia was a UFC heavyweight champion on two occasions, and has racked up 19 huge knockouts over his legendary career.

No. 2: Frank Mir (16-5)

A submission artist, Mir began Brock Lesnar's UFC career with a brutal defeat via kneebar, and finished two-time champion Tim Sylvia with an armbar in their only meeting inside the Octagon.

No. 1: Randy Couture (19-11)

Randy "The Natural" Couture is without a doubt the greatest UFC heavyweight champion of all time. Couture won the title three times, more than any other fighter in UFC history.

Couture held the crown for longer than anyone before surrendering it to Brock Lesnar in November 2008, before then Couture had successfully defended his title three times.