Every now and then significant events in sport come about through tense rivalries between athletes at the top of their game. Take Dave Scott and Mark Allen in triathlon. Dave Scott owned Hawaii Ironman with 6 wins - for a few of those he ran Mark Allen down on the marathon. Mark Allen for his 7th attempt at Hawaii put in some epic training - he theorized that if he was going to race 8+ hours he needed to train on occasion for that long of a period and then slightly more. He also decided to mark Dave the entire race. As it turned out Mark followed Dave on the swim, the bike and 24 miles of the marathon without the two of them speaking a word. On the last hill heading back into Kona Mark pulled away from Dave and went on to win his first World Championship. Both Dave and Mark knocked 20 minutes off the previous Ironman record time - including both running under 2:40 for the marathon. This race was in 1989 and no one has run faster there since. These two great athletes pushed each other to new heights.
Lance Armstrong vs Jan Ulrich. For most of Lance's Tour de France wins Jan Ulrich placed 2nd. They marked each other, were both strong in the mountains and were amongst the best in the time-trial. To outperform Jan, Lance made famous his reconnaisance rides on the key mountain stages beforehand, usually in crappy springtime weather, so he would know every turn and where to best attack Ulrich during the Tour. His attention to detail became his key to victory.
Most recently the men's Australian Open final between Djokovic and Nadal was absolutely incredible. These guys battled for almost 6 hours with incredible athleticism and no-quit attitude. Djokovic prevailed but Nadal almost had it. This was the finest sporting performance I've seen in a while and likely to repeat as both these players enter their prime - should be fun.
I don't exactly have a rivalry with anyone but I generally enjoy when someone doubts me or tries to play mind games. These tactics always have the opposite effect and fuels my effort to have a good performance. The negative mind game attempts are welcomed cause it motivates me to do more. The ironic thing is that person doing it has not quite figured out how ineffective it is and, stubbornly, keeps working on it. I hope they never stop cause it definitely works for me. Here's hoping you find you're own fuel for the fire!