Actually long ago AMD wasn't the underdog. They made CPUs that at a lower clock matched the Pentiums. Like the AMD 233, running at 167 Mhz matched the Pentium 233 running at 233 Mhz.
Remember Cyrix? They ran at 75 Mhz buss while the other CPUs ran at 66 Mgz. Intel had a long way to go but now look what they did.