While many fans would have been content to shell out a handful of cash to watch then-UFC heavyweight champion Brock Lesnar's rematch against Frank Mir in July 2009, the addition of welterweight titleholder Georges St-Pierre made UFC 100 one of the most highly anticipated events in MMA history.
A great main event is key to a fight card's success, but an awesome co-main event to match can take an event to a whole other level. If St-Pierre were removed from UFC 100, the event would have still been a big one, but it wouldn't have been nearly the spectacle that it became with the Canadian on the docket.
Though UFC 100 had a greater impact than almost any other event, there have been plenty of other UFC main event/co-main event combinations that have been just as intriguing. Let's take a look at where UFC 100 stands among the 10 greatest main event/co-main event combinations in UFC history.
The following rankings are based on the star power of the four fighters included the main events and co-main events. Fight outcomes were not taken into consideration when ordering the events.