"It began in the late 1990s when Ortiz verbally and physically took shots at Shamrock's Lion's Den. But it wasn't until the two were matched at UFC 40 that the true nature of their rivalry took shape. Their promotional weight and genuine contempt made UFC 40 Zuffa's most successful pay-per-view before The Ultimate Fighter debuted in 2005. The rematch at UFC 61 (aptly dubbed ""Bitter Rivals"") set a then-UFC record of 775,000 pay-per-view units sold. Though Ortiz easily won both bouts, they were matched once more (free on SpikeTV) and drew 5.7 million viewers."
{}